JP2011213494A - Carbon dioxide gas recovery apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain energy saving by suppressing the amount of heat input from the outside.SOLUTION: The carbon dioxide gas recovery apparatus 1 includes an absorption tower 2 which absorbs carbon dioxide gas in a gas to be separated into an absorption solution thereby generating a rich absorption liquid, and a regeneration tower 3 which heats the rich absorption solution thereby separating out the carbon dioxide gas and regenerating a lean absorption solution. The regeneration tower 3 is equipped with a reboiler system 19 which heats an absorption solution drawn from the regeneration tower 3 and then re-introduces the absorption solution into the regeneration tower 3, and a gas-mixture cooling system 20 which cools a gas mixture of carbon dioxide gas and a vapor fraction of a solute and a solvent of the absorption solution drawn from the regeneration tower 3, condenses the vapor fraction of a solute and a solvent and reintroduces the same into the regeneration tower 3, and outputs carbon dioxide gas. The gas-mixture cooling system 20 is equipped with a gas-mixture compressor 30 which compresses the gas mixture, thereby raising the temperature thereof and yielding a raised-temperature gas mixture. A first heat exchanger 34 which exchanges heat by the absorption solution and the raised-temperature gas mixture is interposed between the reboiler system 19 and the gas-mixture cooling system 20.

Description

The present invention relates to a carbon dioxide gas recovery apparatus that recovers carbon dioxide gas using a CO ₂ chemical absorption separation method.

Conventionally, as this type of carbon dioxide gas recovery device, for example, a configuration as shown in Patent Document 1 below is known. As shown in FIG. 8, this carbon dioxide gas recovery apparatus 1000 introduces and contacts a gas to be separated containing carbon dioxide gas and a lean absorbent, and absorbs the carbon dioxide gas in the gas to be separated. An absorption tower 1001 that generates a rich absorption liquid by absorption into the absorption tower 1001 and a regeneration that is supplied to the lean absorption liquid by heating the rich absorption liquid and separating the carbon dioxide gas by heating the rich absorption liquid And a tower 1002.
Also, the regeneration tower 1002 includes a reboiler system 1003 that draws a lean absorption liquid from the regeneration tower 1002, heats it, and reintroduces it into the regeneration tower 1002, and a solute and solvent (for example, water) of carbon dioxide gas and the absorption liquid. A mixed gas cooling system 1004 for deriving and cooling the mixed gas with the vapor from the regeneration tower 1002, condensing the vapors of the solute and the solvent and reintroducing them into the regeneration tower 1002, and discharging carbon dioxide gas; Is provided.

  In this carbon dioxide gas recovery apparatus 1000, heat that is a heat source for heating the rich absorbent in the regeneration tower 1002 is supplied via the absorbent that is heated by the reboiler system 1003 and reintroduced into the regeneration tower 1002. The The reboiler system 1003 includes a reboiler body 1005 that heats the absorbing liquid using heat supplied from the outside as a heat source.

JP 2003-225537 A

By the way, in the conventional carbon dioxide gas recovery apparatus 1000, the heat supplied from the reboiler body 1005 of the reboiler system 1003 is mainly consumed at the time of heating and regeneration of the absorption liquid in the regeneration tower 1002, and the mixed gas cooling is performed. When the mixed gas is cooled in the system 1004 or when the carbon dioxide gas is discharged from the mixed gas cooling system 1004, it leaks to the outside.
Here, in the conventional carbon dioxide gas recovery apparatus 1000, it is desired that the amount of heat input from the outside in the reboiler system 1003 is suppressed to further save energy.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a carbon dioxide gas recovery device capable of saving energy by suppressing the amount of heat input from the outside.

In order to solve the above problems, the present invention proposes the following means.
The carbon dioxide gas recovery device according to the present invention introduces a gas to be separated containing carbon dioxide gas and a lean absorbing liquid into contact with each other, and absorbs the carbon dioxide gas in the gas to be separated into the absorbing liquid. An absorption tower that generates a rich absorption liquid, and the regeneration is supplied to the lean absorption liquid by supplying the rich absorption liquid from the absorption tower and heating the rich absorption liquid to separate the carbon dioxide gas. A reboiler system in which the absorption liquid is led out from the regeneration tower, heated, and reintroduced into the regeneration tower, the carbon dioxide gas, the solute of the absorption liquid, and the vapor of the solvent. The mixed gas is discharged from the regeneration tower and cooled to condense the vapors of the solute and solvent, reintroduce the condensate into the regeneration tower, and discharge the carbon dioxide gas. A carbon dioxide gas recovery apparatus provided with a mixed gas compressor, wherein the mixed gas cooling system includes a mixed gas compressor that compresses the mixed gas to raise the temperature to obtain a heated mixed gas, and the reboiler A first heat exchanger is provided between the system and the mixed gas cooling system to exchange heat between the absorbing liquid and the temperature-increased mixed gas.
Here, the absorption liquid means a lean absorption liquid, a rich absorption liquid, or a mixed liquid of a lean absorption liquid and a rich absorption liquid.

According to this invention, since the mixed gas cooling system is provided with the mixed gas compressor, the heated mixed gas can be obtained without applying heat from the outside by applying a small amount of external power, and the reboiler system. And the mixed gas cooling system, the first heat exchanger is interposed between the absorption liquid on the reboiler system side and the heated mixed gas on the mixed gas cooling system side. The heated gas mixture can be cooled while heating the absorption liquid.
Thereby, it becomes possible to suppress the amount of heat input from the outside in the reboiler system, and energy saving can be achieved.

  A rich supply path for supplying the rich absorbent from the absorption tower to the regeneration tower; and between the mixed gas cooling system and the rich supply path, after passing through the first heat exchanger. A second heat exchanger that exchanges heat between the temperature rising mixed gas and the rich absorbent may be interposed.

In this case, since the second heat exchanger is interposed between the mixed gas cooling system and the rich supply path, the temperature rising mixed gas on the mixed gas cooling system side, the rich absorbent on the rich supply path side, By exchanging heat, the temperature rising mixed gas can be cooled while heating the rich absorbent supplied to the regeneration tower.
In this way, the rich absorption liquid supplied to the regeneration tower can be preheated by the amount of heat of the mixed gas flowing out of the regeneration tower, so that the amount of heat that the rich absorption liquid needs to receive in the regeneration tower is suppressed. Can do. Therefore, the amount of heat input from outside in the reboiler system can be further suppressed, and further energy saving can be achieved.

  Moreover, since the temperature rising mixed gas on the mixed gas cooling system side passes through the second heat exchanger after passing through the first heat exchanger, for example, the latent heat of the vapor of the solute and the solvent in the temperature rising mixed gas is reduced. After being recovered by the first heat exchanger, the sensible heat and the remaining latent heat of the remaining temperature rising mixed gas composed of the vapors of the uncondensed solute and solvent and carbon dioxide gas can be recovered by the second heat exchanger. it can.

  Further, the carbon dioxide gas recovery device according to the present invention introduces and contacts a gas to be separated containing carbon dioxide gas and a lean absorbing liquid, and the carbon dioxide gas in the gas to be separated becomes an absorbing liquid. An absorption tower that absorbs to produce a rich absorption liquid, and the rich absorption liquid is supplied from the absorption tower, and the rich absorption liquid is heated to separate the carbon dioxide gas to regenerate the lean absorption liquid A reboiler system, a reboiler system for deriving and heating the absorption liquid from the regeneration tower and reintroducing it into the regeneration tower, and the solute and solvent of the carbon dioxide gas and the absorption liquid. The mixed gas with which the vapor component of the gas is discharged from the regeneration tower and cooled, the vapor components of the solute and solvent are condensed and reintroduced into the regeneration tower, and the carbon dioxide gas is discharged. A carbon dioxide gas recovery device provided with a rejection system, comprising a rich supply path for supplying the rich absorbent from the absorption tower to the regeneration tower, wherein the mixed gas cooling system compresses the mixed gas And a mixed gas compressor for raising the temperature to be a temperature rising mixed gas, and heat exchange is performed between the temperature rising mixed gas and the rich absorbing liquid between the mixed gas cooling system and the rich supply path. Three heat exchangers are interposed.

According to this invention, since the mixed gas cooling system is provided with the mixed gas compressor, the heated mixed gas can be obtained without applying heat from the outside by applying a small amount of external power. Since the third heat exchanger is interposed between the cooling system and the rich supply path, heat exchange is performed between the temperature rising mixed gas on the mixed gas cooling system side and the rich absorbent on the rich supply path side. Thus, the heated gas mixture can be cooled while heating the rich absorbent supplied to the regeneration tower.
In this way, the rich absorption liquid supplied to the regeneration tower can be preheated by the amount of heat of the mixed gas flowing out of the regeneration tower, so that the amount of heat that the rich absorption liquid needs to receive in the regeneration tower is suppressed. Can do. Therefore, it becomes possible to suppress the amount of heat input from the outside in the reboiler system, and energy saving can be achieved.

  In addition, a fourth heat exchanger that exchanges heat between the temperature rising mixed gas after passing through the third heat exchanger and the rich absorbent is provided between the mixed gas cooling system and the rich supply path. It may be interposed.

  In this case, since the third heat exchanger and the fourth heat exchanger are interposed between the mixed gas cooling system and the rich supply path, the regeneration tower is determined by the amount of heat of the mixed gas flowing out of the regeneration tower. It is possible to effectively preheat the rich absorbent supplied to the refrigeration, and the amount of heat that the rich absorbent must receive in the regeneration tower can be further suppressed. Therefore, the amount of heat input from outside in the reboiler system can be further suppressed, and further energy saving can be achieved.

  Moreover, since the temperature rising mixed gas on the mixed gas cooling system side passes through the fourth heat exchanger after passing through the third heat exchanger, for example, the latent heat of the vapors of the solute and the solvent in the temperature rising mixed gas is reduced. After recovering with the third heat exchanger, the sensible heat and the remaining latent heat of the remaining heated mixture gas consisting of the vapors of the uncondensed solute and solvent and carbon dioxide gas can be recovered with the fourth heat exchanger. it can.

  Further, heat generated by an exothermic reaction when the absorbing liquid absorbs the carbon dioxide gas in the absorption tower is moved through a heat medium, and the carbon dioxide gas is separated from the rich absorbing liquid in the regeneration tower. A heat pump used as a heat source for the endothermic reaction may be provided.

  In this case, since the heat pump is provided, the heat generated by the exothermic reaction in the absorption tower can be used as a heat source for the endothermic reaction in the regeneration tower. Since the heat generated by the exothermic reaction is equal to the heat of the endothermic reaction, it becomes possible to cancel the reaction heat by exchanging the heat internally. Conventionally, the endothermic reaction is heated from the outside, and the reaction exotherm is discarded in the cooling water. Although it was heated, the reaction heat generated by such water cooling can be used as a heat source for the endothermic reaction necessary for regeneration, further reducing the amount of heat input from the outside and further energy saving. be able to.

  Further, the heat pump is interposed in the absorption tower packing disposed in the absorption tower, and exchanges heat between the heat medium that has been expanded and the temperature has been lowered, and the absorption liquid in the absorption tower. A fifth heat exchanger may be provided.

In this case, since the heat pump includes the fifth heat exchanger, the heat generated by the exothermic reaction in the absorption tower can be received by the heat medium with high loss and high efficiency.
As a result, the heat generated by the exothermic reaction in the absorption tower can be effectively used as a heat source for the endothermic reaction in the regeneration tower, and further energy saving can be achieved. Further, in this case, the absorption rate is improved due to the decrease in the temperature of the absorbing solution, so that the efficiency of the apparatus can be further improved.

  In addition, the heat pump is interposed between the regenerative tower packing disposed in the regeneration tower, heated with the heat medium that has been compressed and the temperature has been increased, and the rich absorbent in the regeneration tower. A sixth heat exchanger to be replaced may be provided.

In this case, since the heat pump includes the sixth heat exchanger, the heat generated by the exothermic reaction moved by the heat medium can be used with high efficiency as a heat source for the endothermic reaction in the regeneration tower with little loss. it can.
As a result, the heat generated by the exothermic reaction in the absorption tower can be effectively used as a heat source for the endothermic reaction in the regeneration tower, and further energy saving can be achieved.

  The absorption tower is provided with a lead-out path for leading the decarbonation gas obtained by separating the carbon dioxide gas from the gas to be separated, and the decarbonation gas is provided between the lead-out path and the heat pump. And a seventh heat exchanger that exchanges heat with the heat medium that has been expanded and the temperature of which has been reduced may be interposed.

In this case, since the seventh heat exchanger is interposed between the lead-out path and the heat pump, by exchanging heat between the decarbonation gas on the lead-out path side and the heat medium on the heat pump side, The derived heat of the decarbonation gas can be received by the heat medium to heat the heat medium.
As a result, it is possible to suppress the heat generated by the exothermic reaction of the absorption tower and transferred to the decarbonation gas from leaking to the outside, and further energy saving can be achieved.

  Further, the absorption tower is provided with a decarbonation gas cleaning system for introducing the cleaning liquid stored at the top of the absorption tower from the absorption tower and cooling it, and then reintroducing it from the top of the absorption tower. Between the decarbonation gas cleaning system and the heat pump, an eighth heat exchanger for exchanging heat between the cleaning liquid and the heat medium expanded and reduced in temperature may be interposed.

In this case, since the decarbonation gas cleaning system is provided in the absorption tower, when the decarbonation gas obtained by separating the carbon dioxide gas from the gas to be separated rises in the absorption tower, It is possible to suppress the solute of the accompanying absorption liquid from flowing out from the top of the absorption tower.
Further, since the eighth heat exchanger is interposed between the decarbonation gas cleaning system and the heat pump, heat exchange is performed between the cleaning liquid on the decarbonation gas cleaning system side and the heat medium on the heat pump side. The heating medium can be heated while cooling the cleaning liquid.
As a result, it is possible to suppress the heat generated by the exothermic reaction of the absorption tower and transferred to the cleaning liquid from leaking to the outside, and further energy saving can be achieved.

A rich supply path for supplying the rich absorbent from the absorption tower to the regeneration tower;
Between the rich supply path and the heat pump, a ninth heat exchanger that exchanges heat between the rich absorbent and the heat medium that has been expanded and reduced in temperature may be interposed.

In this case, since the ninth heat exchanger is interposed between the rich supply path and the heat pump, absorption is performed by exchanging heat between the rich absorption liquid on the rich supply path side and the heat medium on the heat pump side. The heat of the rich absorbent produced by the exothermic reaction of the tower and transferred to the rich absorbent can be received by the heat medium to heat the heat medium.
The carbon dioxide gas recovery device includes a lean supply path for supplying a lean absorbent from the regeneration tower to the absorption tower, and heat is generated between the lean absorbent and the rich absorbent between the lean supply path and the rich supply path. When the amine heat exchange to be exchanged is interposed and the ninth heat exchanger is interposed upstream of the amine heat exchange in the rich supply path, the rich heat absorption liquid passing through the amine heat exchange is passed through the ninth heat exchange. It can be cooled with a vessel. This makes it possible to increase the amount of heat exchange between the rich absorption liquid on the rich supply path side and the lean absorption liquid on the lean supply path side in the amine heat exchange, and the lean absorption liquid on the lean supply path side is effective. The amount of heat recovered as viewed from the regeneration tower can be increased. Therefore, for example, when a lean amine cooler for cooling the lean absorbent is provided downstream of the amine heat exchange in the lean supply path, and the lean absorbent supplied to the absorption tower is cooled before being supplied to the absorption tower. Even so, heat loss to the outside due to this cooling can be reduced.

  Further, the absorption tower is provided with an intercooler system for introducing and cooling the absorbing liquid from the tower intermediate section between the tower top and the tower bottom in the absorption tower and then reintroducing from the tower intermediate section, Between the said intercooler system | strain and the said heat pump, the 10th heat exchanger which heat-exchanges with the said absorption liquid and the said thermal medium expanded and temperature-lowered may interpose.

In this case, since the intercooler system is provided in the absorption tower, the absorption liquid in the middle of the tower can be cooled and reintroduced, and the absorption of carbon dioxide gas by the absorption liquid in the absorption tower is promoted. be able to.
In addition, since the tenth heat exchanger is interposed between the intercooler system and the heat pump, the absorption liquid is cooled by exchanging heat between the absorption liquid on the intercooler system side and the heat medium on the heat pump side. However, the heat medium can be heated.
Thereby, it is possible to suppress the heat generated by the exothermic reaction of the absorption tower and transferred to the absorbing solution from leaking to the outside, and further energy saving can be achieved.

Also, comprising a lean supply path for supplying the lean absorbing liquid from the regeneration tower to the absorption tower,
Between the lean supply path and the heat pump, an eleventh heat exchanger for exchanging heat between the lean absorbing liquid and the heat medium expanded and lowered in temperature may be interposed.

In this case, since the eleventh heat exchanger is interposed between the lean supply path and the heat pump, the heat is exchanged between the lean absorbing liquid on the lean supply path side and the heat medium on the heat pump side. The heat medium can be heated while cooling the absorbing liquid.
Thereby, it becomes possible to cool the lean absorption liquid supplied to the absorption tower, and the absorption of carbon dioxide gas by the lean absorption liquid in the absorption tower can be promoted.

  Further, a twelfth heat exchanger that exchanges heat between the absorbing liquid and the heat medium that has been compressed and raised in temperature may be interposed between the reboiler system and the heat pump.

In this case, since the twelfth heat exchanger is interposed between the reboiler system and the heat pump, by exchanging heat between the reboiler system side absorption liquid and the heat pump side heat medium, Heat can be received by the absorbent and heated.
As a result, the amount of heat input from the outside in the reboiler system can be further suppressed, and further energy saving can be achieved.

  In addition, a rich supply path for supplying the rich absorption liquid from the absorption tower to the regeneration tower is provided, and the rich absorption liquid is compressed and the temperature is increased between the rich supply path and the heat pump. A thirteenth heat exchanger that exchanges heat with the heat medium may be interposed.

In this case, since the thirteenth heat exchanger is interposed between the rich supply path and the heat pump, heat is exchanged between the rich absorption liquid on the rich supply path side and the heat medium on the heat pump side. The rich absorption liquid can be heated by causing the rich absorption liquid supplied to the regeneration tower to receive the heat of the medium.
Thus, since the rich absorption liquid supplied to the regeneration tower can be preheated, the amount of heat that the rich absorption liquid needs to receive in the regeneration tower can be suppressed. Therefore, the amount of heat input from the outside in the reboiler system can be further suppressed, and further energy saving can be achieved.
The carbon dioxide gas recovery device includes a lean supply path for supplying a lean absorbent from the regeneration tower to the absorption tower, and heat is generated between the lean absorbent and the rich absorbent between the lean supply path and the rich supply path. When amine heat exchange to be exchanged is present, the amount of heat in the 13th heat exchanger is added to the amount of heat in the amine heat exchange, resulting in an increase in the preheat amount of the rich absorbent and absorption by the reboiler system. The amount of heat to be given to the liquid can be further suppressed. Therefore, the amount of heat input from the outside in the reboiler system can be further suppressed, and further energy saving can be achieved.

  According to the carbon dioxide gas recovery device of the present invention, it is possible to save energy by suppressing the amount of heat input from the outside.

1 is a schematic view of a carbon dioxide gas recovery device according to a first embodiment of the present invention. It is the schematic of the carbon dioxide gas recovery device concerning a 2nd embodiment of the present invention. It is the schematic of the carbon dioxide gas recovery device concerning a 3rd embodiment of the present invention. It is the schematic of the carbon dioxide gas recovery device concerning a 4th embodiment of the present invention. It is the schematic of the carbon dioxide gas recovery device concerning a 5th embodiment of the present invention. It is the schematic of the carbon dioxide gas recovery device concerning a 6th embodiment of the present invention. It is the schematic of the carbon dioxide gas recovery device concerning a 7th embodiment of the present invention. It is the schematic of the conventional carbon dioxide gas recovery apparatus.

(First embodiment)
Hereinafter, a carbon dioxide gas recovery device according to a first embodiment of the present invention will be described with reference to the drawings. This carbon dioxide gas recovery device recovers carbon dioxide gas from the gas to be separated by absorbing and separating the carbon dioxide gas by a CO ₂ chemical absorption separation method, and removes the carbon dioxide gas from the gas to be separated. Carbon dioxide is generated. In this CO ₂ chemical absorption separation method, an absorbing solution capable of absorbing carbon dioxide gas is used. As this absorbing solution, for example, an amine absorbing solution using monoethanolamine (MEA), diethanolamine (DEA) or the like as a solute and water as a solvent can be used.
In the present embodiment, as described below, energy saving of the carbon dioxide gas recovery device is achieved by so-called self-heat regeneration.

  As shown in FIG. 1, the carbon dioxide gas recovery apparatus 1 brings a gas to be separated into contact with a lean absorbent that can absorb the carbon dioxide gas, and absorbs the carbon dioxide gas in the gas to be separated into the lean absorbent. An absorption tower 2 for generating a rich absorption liquid, and a regeneration tower 3 for supplying the rich absorption liquid from the absorption tower 2 and regenerating the lean absorption liquid by heating the rich absorption liquid to separate carbon dioxide gas. A rich supply path 4 for supplying a rich absorption liquid from the absorption tower 2 to the regeneration tower 3, a lean supply path 5 for supplying a lean absorption liquid from the regeneration tower 3 to the absorption tower 2, and a lean absorption liquid in the absorption tower 2. A heat pump 6 that transfers heat generated by an exothermic reaction when absorbing carbon dioxide gas through a heat medium and that is used as a heat source for an endothermic reaction when carbon dioxide gas is separated from the rich absorbent in the regeneration tower 3; The Eteiru.

In the tower bottom 2a of the absorption tower 2, an introduction path 2d for introducing the gas to be separated is provided. Further, a first nozzle 7 for supplying a lean absorption liquid downward is disposed in the tower top 2b of the absorption tower 2. In the tower intermediate part 2c between the tower top part 2b and the tower bottom part 2a in the absorption tower 2, an absorption tower packing 8 for bringing the lean absorbent and the gas to be separated in contact with each other is disposed.
In addition, the absorption tower 2 is connected to a lead-out path 9 through which the decarbonized gas is led out from the tower top 2 b of the absorption tower 2, and washing water (washing liquid) stored in the tower top 2 b of the absorption tower 2 is led out from the absorption tower 2. A decarbonation gas cleaning system 10 that is reintroduced from the tower top 2b of the absorption tower 2 after cooling is provided.

The decarbonation gas cleaning system 10 includes a liquid receiving tray 11 disposed above the first nozzle 7 and storing cleaning water, and disposed above the liquid receiving tray 11 and supplying cleaning water downward. A second nozzle 12 to be supplied and a pipe 13 for connecting the liquid receiving tray 11 and the second nozzle 12 are provided.
The piping 13 includes a cleaning water circulation pump 13a that transfers cleaning water from the liquid receiving tray 11 to the second nozzle 12 through the piping 13, and a water-cooled cleaning water cooler 15 that cools the cleaning water from the liquid receiving tray 11 side. They are provided in this order toward the second nozzle 12 side.
The washing water is preferably the same as the solute of the absorbing solution (for example, water). Here, the absorption liquid means a lean absorption liquid, a rich absorption liquid, or a mixed liquid of a lean absorption liquid and a rich absorption liquid.

  The rich supply path 4 connects the tower bottom 2 a of the absorption tower 2 and a third nozzle 16 that is disposed in the tower top 3 b of the regeneration tower 3 and supplies a rich absorbent liquid downward. The rich supply path 4 is provided with an absorption tower bottom pump 17 for transferring the rich absorption liquid from the tower bottom 2a of the absorption tower 2 to the third nozzle 16 through the rich supply path 4.

  A regeneration tower packing 18 is disposed in the tower middle part 3c between the tower top 3b and the tower bottom 3a in the regeneration tower 3. The absorption liquid flowing down the surface of the regeneration tower packing 18 includes the solute of the absorption liquid rising in the regeneration tower 3 and the vapor content of the solvent (for example, water), and the mixed gas of the vapor content and carbon dioxide gas. Gas-liquid contact.

  Also, the regenerator 3 draws the absorbing liquid from the regenerator 3 and heats it, reboiler system 19 is reintroduced into the regenerator 3, and the mixed gas is led out from the regenerator 3 and is cooled. A mixed gas cooling system 20 is provided that condenses the vapor and reintroduces the condensate into the regeneration tower 3 and discharges uncondensed carbon dioxide gas.

The reboiler system 19 reintroduces the absorbent from the tower bottom 3 a of the regeneration tower 3 after heating the absorbent. At this time, a part of the heated absorption liquid is flushed, and a part of each of the solute and the solvent of the absorption liquid becomes vapor. The reboiler system 19 includes a liquid receiving tray 21 that is disposed in the bottom 3a of the regeneration tower 3 and stores an absorption liquid, and a steam that is located below the liquid receiving tray 21 in the liquid receiving tray 21 and the tower bottom 3a. And a pipe 23 for connecting the generation portion 22.
The pipe 23 includes a reboiler pump 24 that transfers the absorbing liquid from the liquid receiving tray 21 to the steam generation portion 22 through the pipe 23, and a reboiler body 25 that heats the absorbing liquid using heat supplied from the outside as a heat source. They are provided in this order from the liquid receiving tray 11 side toward the vapor generating portion 22 side.
In the illustrated example, the reboiler body 25 is constituted by a heat exchanger interposed between the reboiler system 19 and a reboiler pipe 26 through which a high-temperature fluid (for example, saturated steam) supplied from the outside flows. The reboiler pipe 26 is provided with a steam trap 27 on the downstream side of the reboiler body 25.

The mixed gas cooling system 20 is disposed above the third nozzle 16, and supplies the condensate, which is the vapor content of the condensed solute and solvent, downward, and the regeneration tower 3. And a pipe 29 for connecting the top of the tower and the fourth nozzle 28 to each other.
In the pipe 29, a mixed gas compressor (mixed gas compressor) 30 that raises the temperature by compressing the mixed gas to be a heated mixed gas, and a pressure reduction / expansion valve 31 that lowers the temperature by expanding the heated mixed gas. And a gas-liquid separator 32 that separates the condensate and carbon dioxide gas, and a condensate circulation pump 29a that transfers the condensate from the gas-liquid separator 32 to the fourth nozzle 28 through the pipe 29. Are provided in this order from the tower top side toward the fourth nozzle 28 side.
The gas-liquid separator 32 is provided with a discharge path 33 for discharging the carbon dioxide gas separated by the gas-liquid separator 32.

In the present embodiment, a condensing heat exchanger (first heat exchanger) 34 that performs heat exchange between the absorbing liquid and the temperature rising mixed gas is interposed between the reboiler system 19 and the mixed gas cooling system 20. .
In the illustrated example, the absorption liquid before being heated by the reboiler body 25 passes through the condensation heat exchanger 34. The condensing heat exchanger 34 is interposed between the reboiler pump 24 and the reboiler body 25 in the pipe 23 of the reboiler system 19, and the mixed gas compressor 30 and the pressure reducing / expansion valve in the pipe 29 of the mixed gas cooling system 20. 31 is interposed.

The lean supply path 5 connects the tower bottom 3 a of the regeneration tower 3 and the first nozzle 7 in the absorption tower 2, and the lean supply path 5 is connected to the second bottom from the tower bottom 3 a of the regeneration tower 3. A regeneration tower bottom pump 35 for transferring the lean absorption liquid to the one nozzle 7 through the lean supply path 5 is provided.
Further, between the lean supply path 5 and the rich supply path 4, there is an amine heat exchanger 36 that exchanges heat between the lean absorbent and the rich absorbent.

  The heat pump 6 is interposed in the absorption tower internal heat exchange (fifth heat exchanger) 37 interposed in the absorption tower packing 8 in the absorption tower 2 and in the regeneration tower packing 18 in the regeneration tower 3. And a pair of pipes 39 and 40 for connecting the absorption tower internal heat exchange 37 and the regeneration tower internal heat exchange 38.

The heat exchange 37 inside the absorption tower exchanges heat between the heat medium which is interposed so as to cut through the absorption tower packing 8 and is expanded and whose temperature is lowered, and the absorption liquid in the absorption tower 2.
In addition, the regeneration tower internal heat exchanger 38 is heat-exchanged between the heat medium that is interposed so as to cut through the regeneration tower packing 18 and is compressed and whose temperature is increased, and the absorbent in the regeneration tower 3.

  Of the pair of pipes 39, 40, one pipe 39 connects the upper side of the regeneration tower internal heat exchange 38 and the lower side of the absorption tower internal heat exchange 37, and expands the heat medium into the pipe 39. A heating medium expansion valve 41 is provided to lower the temperature by causing the temperature to decrease. The other pipe 40 connects the upper side of the absorption tower internal heat exchange 37 and the lower side of the regeneration tower internal heat exchange 38, and the pipe 40 has heat that increases the temperature by compressing the heat medium. A medium compressor 42 is provided.

  As the heat medium, for example, the heat generated by the exothermic reaction in the absorption tower 2 is recovered as latent heat of evaporation by evaporating in the heat exchange 37 inside the absorption tower and condensed in the heat exchange 38 inside the regeneration tower. A fluid capable of generating heat of condensation and using the heat of condensation as a heat source for the endothermic reaction in the regeneration tower 3 is preferable. Examples of such fluid include pentane and water.

Next, the operation of the carbon dioxide gas recovery apparatus 1 configured as described above will be described.
First, the flow of the absorption liquid will be described starting from the absorption tower 2.
First, in the absorption tower 2, the gas to be separated supplied to the tower bottom 2a rises inside, and the lean absorbent supplied from the first nozzle 7 in the tower top 2b falls inside. In this process, the gas to be separated comes into contact with the lean absorbent, and the carbon dioxide gas in the gas to be separated is absorbed by the lean absorbent and an exothermic reaction occurs.

  Here, in the present embodiment, the absorption tower packing 8 is disposed in the tower middle portion 2 c of the absorption tower 2. The absorption tower packing 8 has, for example, a fin configuration having a large number of narrow gaps, a large fin surface area per volume, and the gap is configured so that the angle of the flow path changes regularly. The turbulence of the flow occurs. On the surface of the absorption tower packing 8, the absorption liquid flows down on the fins while forming a wet wall, and is brought into gas-liquid contact with the gas to be separated that rises in the absorption tower 2. Moreover, the absorption tower packing 8 has a structure in which the gap between the wetting walls is narrow and the traveling angle changes at a constant pitch, thereby disturbing the flow of gas and liquid and improving the efficiency of gas-liquid contact. Therefore, on the surface of the absorption tower packing 8, the rising separation gas and the falling absorption liquid are easily in contact with each other, and the absorption of carbon dioxide gas by the absorption liquid is promoted.

Thereby, a rich absorption liquid and decarbonation gas are generated. Of these, the decarbonation gas rises toward the top 2 b of the absorption tower 2 and is led out through the lead-out path 9.
In the present embodiment, since the decarbonation gas cleaning system 10 is provided in the absorption tower 2, the inside of the tower top 2b of the absorption tower 2 is cooled by the cleaning water cooled and re-introduced by the water-cooled cleaning water cooler 15. can do. Therefore, for example, even if the solute in the absorption liquid scatters or evaporates and rises accompanying the decarbonation gas, it can be removed by washing and cooling before reaching the lead-out path 9. It is possible to suppress the solute therein from flowing out from the tower top 2 b of the absorption tower 2 through the outlet path 9.

  On the other hand, the rich absorbent produced together with the decarbonation gas descends in the absorption tower 2 and is stored in the tower bottom 2a, and then passes through the rich supply path 4 to the third nozzle 16 in the tower top 3b of the regeneration tower 3. Supplied. Here, in the present embodiment, the amine heat exchanger 36 is interposed between the lean supply path 5 and the rich supply path 4, and the rich absorption liquid exchanges heat with the lean absorption liquid on the lean supply path 5 side. Heated while cooling the lean absorbent.

  In the regeneration tower 3, the rich absorbing liquid supplied from the third nozzle 16 descends, and the absorbing liquid heated by the reboiler system 19 is reintroduced from the tower bottom 3a. At this time, a part of the heated absorption liquid is flushed in the vapor generation part 22, a part of each of the solute and the solvent of the absorption liquid becomes a vapor, and the regenerated carbon dioxide becomes a gas, To rise. In this process, the rich absorption liquid and the vapors of the solute and solvent come into contact with each other, and an endothermic reaction of desorption regeneration takes place using the heat of condensation of the vapors of the solute and solvent as a heat source. Are separated.

  Here, in this embodiment, the regeneration tower packing 18 is disposed in the tower middle portion 3 c of the regeneration tower 3. The regeneration tower packing 18 has, for example, a fin configuration having a large number of narrow gaps, a large fin surface area per volume, and the gap is configured so that the angle of the flow path changes regularly. The turbulence of the flow occurs. On the surface of the regenerative tower packing 18, the absorbing solution flows down on the fins while forming a wet wall, contacts the vapor of the solute and the solvent rising in the regenerator 3, and is efficient due to the size of the surface area and flow disturbance. Gas-liquid contact is made and the separation and release of carbon dioxide is promoted.

  Thereby, a rich absorption liquid is isolate | separated into a lean absorption liquid and carbon dioxide gas. Of these, the carbon dioxide gas is mixed with the solute and the vapor of the solvent to become a mixed gas, and rises in the regeneration tower 3.

  This mixed gas is introduced into the pipe 29 of the mixed gas cooling system 20 from the top of the regeneration tower 3 and then compressed in the course of passing through this pipe 29 to be heated and mixed by the mixed gas compressor 30. It becomes gas. Thereafter, the temperature rising mixed gas is cooled while heating the absorption liquid by exchanging heat with the absorption liquid on the reboiler system 19 side in the condensation heat exchanger 34. After that, the temperature rising mixed gas is expanded by the pressure reduction / expansion valve 31 and the temperature is lowered.

  By the above, the vapor | steam part of the said solute and solvent in temperature rising mixed gas is condensed, and it becomes a condensate, This condensate and the non-condensed carbon dioxide main gas (temperature rising mixed gas) which mainly consisted of carbon dioxide gas Are separated by the gas-liquid separator 32. The condensate is reintroduced into the regeneration tower 3 from the fourth nozzle 28, and uncondensed carbon dioxide main gas is discharged to the outside through the discharge path 33.

  On the other hand, the absorption liquid descending in the regeneration tower 3 is stored in the tower bottom 3 a and then led out from the regeneration tower 3 a as a separated and regenerated lean absorption liquid, and passes through the lean supply path 5 in the tower top 2 b of the absorption tower 2. To the first nozzle 7. At this time, the lean absorbing liquid is cooled while preheating the rich absorbing liquid by exchanging heat with the rich absorbing liquid on the rich supply path 4 side by the amine heat exchanger 36. As a result, when viewed from the regeneration tower 3 side, the heat taken out by the lean absorbent can be recovered as preheating of the rich absorbent supplied from the outside.

Next, the flow of the heat medium in the heat pump 6 will be described with the heat medium expansion valve 41 as a starting point.
The heat medium whose temperature has been lowered by the heat medium expansion valve 41 passes through the one pipe 39 and then exchanges heat with the absorbing liquid while moving from the lower side to the upper side of the heat exchange 37 inside the absorption tower. Thus, while cooling the absorption liquid, the heat of the exothermic reaction generated when the absorption liquid chemically absorbs carbon dioxide is received and evaporated, and then the heat exchange inside the regeneration tower is performed through the other pipe 40. It moves to the lower side of 38. At this time, the heat medium is compressed by the heat medium compressor 42 and the temperature is increased.

  The heat medium moves from the lower side to the upper side of the heat exchanger 38 inside the regeneration tower and exchanges heat with the absorbing liquid, thereby heating the absorbing liquid and consuming the heat as a heat source for the endothermic reaction. After cooling and condensing in the above, it moves toward the lower side of the heat exchange 37 inside the absorption tower through the one pipe 39. At this time, the pressure of the heat medium is lowered by the heat medium expansion valve 41, and the temperature is lowered again to become a gas / liquid mixed fluid.

As described above, according to the carbon dioxide gas recovery apparatus 1 according to the present embodiment, the mixed gas cooling system 20 includes the mixed gas compressor 30, so that it is heated from the outside by applying a slight external power. Therefore, since the condensation heat exchanger 34 is interposed between the reboiler system 19 and the mixed gas cooling system 20, the mixed gas is mixed with the absorption liquid on the reboiler system 19 side. By performing heat exchange with the temperature rising mixed gas on the gas cooling system 20 side, the temperature rising mixed gas can be cooled while heating the absorption liquid.
In this way, the rich absorption liquid supplied to the regeneration tower 3 can be preheated by the amount of heat of the mixed gas flowing out of the regeneration tower 3, so that the amount of heat input from the outside in the reboiler system 19 can be suppressed. Can be achieved and energy saving can be achieved.

  Further, since the heat pump 6 is provided, the heat generated by the exothermic reaction in the absorption tower 2 can be used as a heat source for the endothermic reaction in the regeneration tower 3. Since the heat generated by the exothermic reaction is equal to the heat of the endothermic reaction, it becomes possible to cancel the reaction heat by exchanging inside, and conventionally, the heat generated from the reaction is cooled from the outside while the heat generated from the reaction is cooled. Although it was wasted in water, the reaction heat generated by such water cooling can be used as a heat source for the endothermic reaction necessary for regeneration, further reducing the amount of heat input from the outside and further saving energy. Can be achieved.

Moreover, since the heat pump 6 includes the absorption tower internal heat exchange 37, the heat generated by the exothermic reaction in the absorption tower 2 can be received by the heat medium with high loss and high efficiency.
Further, since the heat pump 6 includes the regeneration tower internal heat exchange 38, the heat generated by the exothermic reaction transferred by the heat medium is utilized with high efficiency as a heat source for the endothermic reaction in the regeneration tower 3 with little loss. be able to.
As described above, the heat generated by the exothermic reaction in which the absorption liquid chemically absorbs carbon dioxide in the absorption tower 2 is absorbed in the regeneration tower 3 without consuming the energy of waste heat to the cooling water while being externally heated. It can be effectively used as a heat source for an endothermic reaction for separating and regenerating carbon dioxide from the carbon dioxide, and further energy saving can be achieved.

Here, the above effects can be generalized and described as the following two items.
(1) Self-heat regeneration effect of reaction heat The reaction heat generation amount in the absorption tower 2 is equal to the reaction heat absorption amount in the regeneration tower 3. Therefore, the reaction heat conventionally applied by heating from the outside with a little power required for the heat pump 6 can be covered by exchange inside the process, and exchange of heat with the outside can be eliminated. As a result, the amount of external heat applied in the reboiler system 19 of the regeneration tower 3 is reduced as compared with the conventional case.
(2) Self-regenerative regeneration of latent heat required for tower operation The amount of heat of the mixed gas flowing out from the top 3b of the regeneration tower 3 was consumed from the outside by the reboiler system 19 to evaporate the solute and the solvent in the absorption liquid. Equivalent to the amount of heat minus the amount of reaction endotherm required for regeneration of the absorbent. Therefore, if the heated mixed gas is obtained with a slight power for compressing the mixed gas and the heat of the mixed gas can be given to the reboiler system 19 by the condensation heat exchanger 34, the amount of heat to be applied from the outside by the reboiler system 19 Is reduced. Strictly speaking, the amount of heat to be applied is the amount of recovery leakage heat in the amine heat exchanger 36 (the sensible heat amount of the lean absorbing liquid flowing out from the amine heat exchanger 36 and the sensible heat amount of the rich absorbing liquid flowing into the amine heat exchanger 36). The amount of heat is commensurate with the sum of the amount of heat dissipated around the regeneration tower 3.

(Second Embodiment)
Next, a carbon dioxide gas recovery device according to a second embodiment of the present invention will be described.
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different points will be described.

  As shown in FIG. 2, in the carbon dioxide gas recovery apparatus 100 of the present embodiment, the pressure reduction / expansion valve 31 of the mixed gas cooling system 20 is provided in the discharge passage 33 and the gas in the pipe 29 of the mixed gas cooling system 20 A level control valve 101 is provided between the liquid separator 32 and the fourth nozzle 28 instead of the condensate circulation pump 29a.

Further, the heat pump 6 does not include the absorption tower internal heat exchange 37. In the present embodiment, a decarbonation gas cooler (seventh heat exchanger) that exchanges heat between the decarbonization gas and the expanded heat-reduced heat medium between the outlet path 9 and the heat pump 6. 102 is interposed. Further, a wash water cooler (eighth heat exchanger) 103 for exchanging heat between the wash water and the expanded heat-reduced heat medium is interposed between the decarbonation gas cleaning system 10 and the heat pump 6. is doing. Further, between the rich supply path 4 and the heat pump 6, there is a rich amine heat exchanger (9th heat exchanger) 104 for exchanging heat between the rich absorbent and the expanded and lowered temperature medium. Intervene.
The decarbonation gas cooler 102, the washing water cooler 103, and the rich amine heat exchanger 104 pass through the heat medium expanded by the heat medium expansion valve 41 and lowered in temperature in the heat pump 6, and the heat that the heat medium receives heat. Intervenes on the collection side.

  In the illustrated example, the heat pump 6 includes a plurality of pipes 105, 106, 107, and 108, and a heat medium distributor 109 and a heat medium collector 110 that connect the pipes 105, 106, 107, and 108. The plurality of pipes 105, 106, 107, and 108 connect the first pipe 105 that connects the upper side of the heat exchange 38 inside the regeneration tower and the heat medium distributor 109, the heat medium distributor 109, and the heat medium collector 110. It consists of two branch pipes 106 and 107 to be connected, and a second pipe 108 that connects the heat medium collector 110 and the lower side of the regeneration tower internal heat exchanger 38.

  Of the two branch pipes 106 and 107, one branch pipe 106 is provided with a decarboxylation gas cooler 102 and a washing water cooler 103 in this order from the heat medium distributor 109 side to the heat medium collector 110 side. In addition, a rich amine heat exchanger 104 is interposed in the other branch pipe 107. The first pipe 105 is provided with the heat medium expansion valve 41, and the second pipe 108 is provided with the heat medium compressor 42.

In the illustrated example, in the decarbonation gas cleaning system 10 provided in the absorption tower 2, a cleaning water cooler 103 is interposed between the cleaning water circulation pump 13a and the second nozzle 12 in the pipe 13, The water-cooled washing water cooler 15 is not provided.
A rich amine heat exchanger 104 is interposed in the rich supply path 4 downstream of the absorption tower bottom pump 17 and upstream of the amine heat exchanger 36.

Next, the operation of the carbon dioxide gas recovery apparatus 100 configured as described above will be described. Here, the flow of the heat medium of the heat pump 6 will be described with the heat medium expansion valve 41 as a starting point.
The heat medium whose temperature has been lowered by the heat medium expansion valve 41 passes through the first pipe 105 and then passes through two branch pipes 106 and 107 branched by the heat medium distributor 109.

Among these, the heat medium passing through the one branch pipe 106 exchanges heat with the decarbonation gas on the outlet path 9 side in the decarbonation gas cooler 102, so that the heat of the decarbonation gas derived from the absorption tower 2 is increased. Received and heated. Thereafter, the heat medium is further heated while cooling the washing water by exchanging heat with the washing water on the decarbonation gas washing system 10 side in the washing water cooler 103.
The heat medium passing through the other branch pipe 107 receives the heat of the rich absorbent flowing out from the absorption tower 2 in the rich amine heat exchanger 104 and is heated.

  Then, the heat medium that has passed through both branch pipes 106 and 107 joins at the heat medium collector 110. The heat medium merged in the heat medium collector 110 moves to the lower side of the regeneration tower internal heat exchange 38 through the second pipe 108. At this time, the temperature of the heat medium is raised by the heat medium compressor 42. The heat medium moves from the lower side to the upper side of the heat exchanger 38 inside the regeneration tower and exchanges heat with the absorbing liquid, thereby heating the absorbing liquid and consuming the heat with the heat source of the endothermic reaction. After being cooled, the first medium moves through the first pipe 105 toward the heat medium distributor 109. At this time, the temperature of the heat medium is lowered again by the heat medium expansion valve 41.

As described above, according to the carbon dioxide gas recovery device 100 according to the present embodiment, since the decarbonation gas cooler 102 is interposed between the lead-out path 9 and the heat pump 6, By exchanging heat between the decarboxylation gas and the heat medium on the heat pump 6 side, the heat medium can receive the heat of the decarboxylation gas derived from the absorption tower 2 to heat the heat medium.
Thereby, it is possible to suppress the heat generated by the exothermic reaction of the absorption tower 2 and transferred to the decarbonized gas from leaking to the outside, and further energy saving can be achieved.

Further, since the cleaning water cooler 103 is interposed between the decarbonation gas cleaning system 10 and the heat pump 6, the heat is generated by the cleaning water on the decarbonation gas cleaning system 10 side and the heat medium on the heat pump 6 side. By exchanging, the heat medium can be heated while cooling the washing water.
As a result, it is possible to suppress the heat generated by the exothermic reaction of the absorption tower 2 and transferred from the decarbonized gas to the washing water from leaking to the outside, and further energy saving can be achieved.

Further, since the rich amine heat exchanger 104 is interposed between the rich supply path 4 and the heat pump 6, heat exchange is performed between the rich absorbent on the rich supply path 4 side and the heat medium on the heat pump 6 side. By doing so, the heat of the rich absorption liquid generated by the exothermic reaction of the absorption tower 2 and delivered to the rich absorption liquid can be received by the heat medium and the heat medium can be heated.
In this embodiment, since the rich amine heat exchanger 104 is interposed upstream of the amine heat exchanger 36 in the rich supply path 4, the rich absorbent liquid passing through the amine heat exchanger 36 is passed through the rich amine heat exchanger 36. It can be cooled by the exchanger 104. Thereby, in the amine heat exchanger 36, it becomes possible to increase the amount of heat exchange between the rich absorbent on the rich supply path 4 side and the lean absorbent on the lean supply path 5 side, and the lean supply path 5 side Thus, the lean absorption liquid can be effectively cooled, and the amount of heat recovered as viewed from the regeneration tower can be increased. Therefore, for example, a lean amine cooler (not shown) that cools the lean absorbent is provided downstream of the amine heat exchanger 36 in the lean supply passage 5, and the lean absorbent supplied to the absorption tower 2 is supplied to the absorption tower 2. Even in the case of cooling in advance, heat loss to the outside due to this cooling can be reduced.

In the present embodiment, the heat of decarboxylation gas and absorption liquid led out from the inside of the absorption tower 2 is received by the decarbonation gas cooler 102, the washing water cooler 103, and the rich amine heat exchanger 104. Yes. Therefore, the heat generated by the exothermic reaction in the absorption tower 2 can be received by the heat medium without providing the absorption tower internal heat exchange 37. Thereby, for example, the carbon dioxide gas recovery apparatus 100 can be simplified.
In the present embodiment, the heat pump 6 does not include the absorption tower internal heat exchange 37, but may include it.

(Third embodiment)
Next, a carbon dioxide gas recovery device according to a third embodiment of the present invention will be described.
Note that in the third embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, description thereof is omitted, and only different points will be described. Further, in FIG. 3, for the sake of easy viewing, a part of the same part as the component in the second embodiment is not shown.

  As shown in FIG. 3, in the carbon dioxide gas recovery apparatus 200 of the present embodiment, the absorption tower packing 8 is divided into two vertically divided in the tower middle part 2 c of the absorption tower 2, and the absorption tower 2. Is provided with an intercooler system 201 for introducing the absorption liquid from the tower intermediate part 2c of the absorption tower 2 and cooling it, and then reintroducing it from the tower intermediate part 2c.

The intercooler system 201 is disposed between the divided absorption tower packings 8 and has a liquid receiving tray 202 in which the absorbing liquid is stored, and is disposed below the liquid receiving tray 202 and supplies the absorbing liquid downward. And a pipe 204 that connects the liquid receiving tray 202 and the fifth nozzle 203 to each other.
The pipe 204 is provided with an intercooler pump 205 that transfers the absorption liquid from the liquid receiving tray 202 to the fifth nozzle 203 through the pipe 204.

  And in this embodiment, between the intercooler system | strain 201 and the heat pump 6, the heat-medium cooling type intercooler (10th heat exchanger) which heat-exchanges with an absorption liquid and the heat medium expanded and temperature-lowered. 206 is interposed. Further, between the lean supply path 5 and the heat pump 6, a heat medium cooled lean amine cooler (eleventh heat exchanger) that exchanges heat between the lean absorbing liquid and the heat medium that has been expanded and lowered in temperature. 207 is interposed.

  In the illustrated example, the heat pump 6 includes five branch pipes 208, and each of the branch pipes 208 includes the decarbonation gas cooler 102, the washing water cooler 103, the rich amine heat exchanger 104, and the heat medium cooling. Either a type intercooler 206 or a heat medium cooling type lean amine cooler 207 is interposed.

In the intercooler system 201, a heat medium cooling type intercooler 206 is interposed between the intercooler pump 205 and the fifth nozzle 203 in the pipe 204.
Further, a heat medium cooling type lean amine cooler 207 is interposed in the lean supply path 5 downstream of the amine heat exchanger 36.

Next, the operation of the carbon dioxide gas recovery device 200 configured as described above will be described. Here, the flow of the heat medium of the heat pump 6 will be described from the heat medium expansion valve 41 as a starting point until the heat medium collector 110 is reached.
The heat medium whose temperature has been lowered by the heat medium expansion valve 41 passes through the second pipe 108 and then passes through five branch pipes 208 branched by the heat medium distributor 109.

Among these, the heat medium passing through the branch pipe 208 provided with the heat medium cooling intercooler 206 is heated while cooling the absorption liquid by exchanging heat with the absorption liquid in the heat medium cooling intercooler 206.
Further, the heat medium passing through the branch pipe 208 in which the heat medium cooling type lean amine cooler 207 is interposed is heated in the heat medium cooling type lean amine cooler 207 while cooling the lean absorbent.
Then, the heat medium that has passed through each branch pipe 208 joins in the heat medium collector 110.

As described above, according to the carbon dioxide gas recovery device 200 according to the present embodiment, since the heat medium cooling type lean amine cooler 207 is interposed between the lean supply path 5 and the heat pump 6, By exchanging heat between the lean absorbing liquid on the supply path 5 side and the heat medium on the heat pump 6 side, the heat medium can be heated while cooling the lean absorbing liquid.
Thereby, the heat | fever of the lean absorption liquid which was waste heat to cooling water conventionally can be collect | recovered as heat of a heat medium, without waste heat. Moreover, it becomes possible to cool the lean absorption liquid supplied to the absorption tower 2, and the absorption of the carbon dioxide gas by the absorption liquid in the absorption tower 2 can be promoted.

  Further, since the intercooler system 201 is provided in the absorption tower 2, it becomes possible to re-introduce the absorption liquid in the tower intermediate part 2 c and to absorb carbon dioxide gas by the absorption liquid in the absorption tower 2. Can be promoted more.

In addition, since the heat medium cooling type intercooler 206 is interposed between the intercooler system 201 and the heat pump 6, heat exchange is performed between the absorbing liquid on the intercooler system 201 side and the heat medium on the heat pump 6 side. The heating medium can be heated while cooling the absorbing liquid.
Thereby, it becomes possible to suppress the heat generated by the exothermic reaction of the absorption tower 2 and delivered to the absorbing liquid from leaking to the outside, and further energy saving can be achieved.

(Fourth embodiment)
Next, a carbon dioxide gas recovery device according to a fourth embodiment of the present invention will be described.
In the fourth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different points will be described.

  As shown in FIG. 4, in the carbon dioxide gas recovery device 300 of the present embodiment, the flow of the rich absorbent is branched to a portion located between the absorption tower bottom pump 17 and the amine heat exchanger 36 in the rich supply path 4. A rich amine distributor 301, two rich branch paths 302 and 303 through which the branched rich absorbing liquid flows, and a rich amine collector 304 into which the rich branch paths 302 and 303 join together.

Of the two rich branch paths 302 and 303, between the rich branch path 302 and the lean supply path 5, there is a first rich amine heat exchanger 305 that exchanges heat between the rich absorbent and the lean absorbent. ing. The first rich amine heat exchanger 305 is interposed downstream of the amine heat exchanger 36 in the lean supply passage 5, and the rich absorbent on the one rich branch passage 302 side and the lean on the lean supply passage 5 side. Lean that is supplied to the absorption tower 2 and causes an exothermic reaction in the absorption tower 2 while preheating the rich absorption liquid that is supplied to the regeneration tower 3 and causes an endothermic reaction in the regeneration tower 3 by exchanging heat with the absorption liquid. The absorbing liquid can be cooled.
A reboiler distributor 306 is provided between the reboiler pump 24 and the condensation heat exchanger 34 in the pipe 23 of the reboiler system 19 provided in the regeneration tower 3. A branch pipe 307 connected to the tower bottom 3a of the tower 3 is branched.

In the present embodiment, between the reboiler system 19 and the heat pump 6, a heat medium reboiler heater (the twelfth heat exchanger) that exchanges heat between the absorbing liquid and the heat medium that has been compressed and raised in temperature. 308 is interposed. Further, between the rich supply path 4 and the heat pump 6, a second rich amine heat exchange (a thirteenth heat exchanger) 309 that exchanges heat between the rich absorbent and the heat medium that has been compressed and the temperature is increased. Is intervening.
The heat medium reboiler heater 308, the second rich amine heat exchanger 309, and the regeneration tower internal heat exchanger 38 are passed through the heat medium compressed by the heat medium compressor 42 in the heat pump 6 and the temperature is increased. It is located on the heat supply side that delivers heat.

  In the illustrated example, the heat pump 6 includes a plurality of pipes 310, 311, 312, 313, and 314, and a heat medium distributor 315 and a heat medium collector 316 that connect the pipes. The plurality of pipes 310, 311, 312, 313, and 314 include three branch pipes 310, 311, and 312 that connect the heat medium distributor 315 and the heat medium collector 316, the heat medium collector 316, and the absorption tower internal heat. The first pipe 313 connects the lower side of the cross 37 and the second pipe 314 connects the upper side of the heat exchange 37 inside the absorption tower and the heat medium distributor 315.

Among the three branch pipes 310, 311, 312, the regeneration tower internal heat exchanger 38 is provided at an intermediate portion of the first branch pipe 310, and a heat medium reboiler heater 308 is provided in the second branch pipe 311. Is installed, and a second rich amine heat exchanger 309 is interposed in the third branch pipe 312. The first pipe 313 is provided with the heat medium expansion valve 41, and the second pipe 314 is provided with the heat medium compressor 42.
In the illustrated example, in the reboiler system 19, a heating medium reboiler heater 308 is interposed in the branch pipe 307, and in the rich supply path 4, one of the rich branch paths 302, 303 is the one rich branch. A second rich amine heat exchanger 309 is interposed in the other rich branch path 303 different from the path 302. The second rich amine heat exchanger 309 is interposed upstream of the amine heat exchanger 36 in the rich supply path 4.

  Next, the operation of the carbon dioxide gas recovery device 300 configured as described above will be described. Here, the flow of the heat medium of the heat pump 6 will be described with the heat medium expansion valve 41 as a starting point.

  The heat medium whose temperature has been lowered by the heat medium expansion valve 41 passes through the first pipe 313 and then exchanges heat with the absorbing liquid while moving from the lower side to the upper side of the heat exchange 37 inside the absorption tower. Then, the heat of the exothermic reaction is received while cooling the absorbing liquid, and then moves to the heat medium distributor 315 through the second pipe 314. At this time, the temperature of the heat medium is raised by the heat medium compressor 42. The heat medium is branched by the heat medium distributor 315 and passes through the branch pipes 310, 311, and 312.

Among these, the heat medium passing through the first branch pipe 310 moves from the lower side to the upper side of the heat exchange 38 inside the regeneration tower, and exchanges heat with the absorbing liquid, whereby the heat is a heat source for the endothermic reaction. To the rich absorbent and heat.
Further, the heat medium passing through the second branch pipe 311 exchanges heat with the absorption liquid on the reboiler system 19 side in the heat medium type reboiler heater 308, thereby transferring the heat to the absorption liquid and heating it.
Furthermore, the heat medium passing through the third branch pipe 312 exchanges heat with the rich absorption liquid on the rich supply path 4 side, thereby delivering the heat to the rich absorption liquid and heating it.

  Then, the heat medium that has passed through the branch pipes 310, 311, and 312 joins at the heat medium collector 316. The heat medium merged in the heat medium collector 316 moves toward the lower side of the heat exchange 37 inside the absorption tower through the first pipe 313. At this time, the temperature of the heat medium is lowered again by the heat medium expansion valve 41.

As described above, according to the carbon dioxide gas recovery apparatus 300 according to the present embodiment, since the heat medium reboiler heater 308 is interposed between the reboiler system 19 and the heat pump 6, the reboiler system 19 side. By exchanging heat between the absorption liquid and the heat medium on the heat pump 6 side, the heat of the heat medium can be received by the absorption liquid and the absorption liquid can be heated.
As a result, the amount of heat input from the outside in the reboiler system 19 can be further suppressed, and further energy saving can be achieved.

Further, since the second rich amine heat exchange 309 is interposed between the rich supply path 4 and the heat pump 6, heat is generated between the rich absorbent on the rich supply path 4 side and the heat medium on the heat pump 6 side. By exchanging, the heat of the heat medium can be received by the rich absorption liquid supplied to the regeneration tower 3 and the rich absorption liquid can be heated.
Thus, since the rich absorption liquid supplied to the regeneration tower 3 can be preheated, the amount of heat that the rich absorption liquid needs to receive in the regeneration tower 3 can be suppressed. Therefore, the amount of heat input from the outside in the reboiler system 19 can be further suppressed, and further energy saving can be achieved.
Further, when the amine heat exchanger 36 is interposed between the lean supply path 5 and the rich supply path 4 as in the present embodiment, the second rich amine heat exchanger is included in the heating amount in the amine heat exchanger 36. As a result of adding the heating amount at 309, the preheating amount of the rich absorption liquid increases, and the amount of heat to be given to the absorption liquid by the reboiler system 19 can be further suppressed. Therefore, the amount of heat input from the outside in the reboiler system 19 can be further suppressed, and further energy saving can be achieved.

(Fifth embodiment)
Next, a carbon dioxide gas recovery device according to a fifth embodiment of the present invention will be described.
In the fifth embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, description thereof is omitted, and only different points will be described.

  As shown in FIG. 5, in the carbon dioxide gas recovery apparatus 400 according to the present embodiment, the reboiler is disposed between the reboiler pump 24 and the condensation heat exchanger 34 in the pipe 23 of the reboiler system 19 provided in the regeneration tower 3. A distributor 401 is provided, and a branch pipe 402 connected to the tower bottom 3 a of the regeneration tower 3 is branched from the reboiler distributor 401.

Further, the heat pump 6 does not include the regeneration tower internal heat exchange 38. In the present embodiment, between the reboiler system 19 and the heat pump 6, a heat medium reboiler heater (the twelfth heat exchanger) that exchanges heat between the absorbing liquid and the heat medium that has been compressed and raised in temperature. 403 is interposed.
In the illustrated example, the plurality of pipes 404 and 405 of the heat pump 6 are connected to the heat medium collector 110 and the heat medium distributor 109 and the main pipe 404 provided with the heat medium compressor 42 and the heat medium distributor. 109 and three branch pipes 405 connecting the heat medium collector 110.

The main pipe 404 is provided with a heat medium expansion turbine 406 that lowers the temperature by expanding the heat medium. The heat medium expansion turbine 406 obtains rotational power when the heat medium is expanded. The heat medium reboiler heater 403 is interposed between the heat medium compressor 42 and the heat medium expansion turbine 406 in the main pipe 404.
Each of the branch pipes 405 is provided with any one of a heat medium cooling type decarboxylation gas cooler 102, a heat medium cooling type washing water cooler 103, and a heat medium cooling type rich amine heat exchanger 104. .

  Next, the operation of the carbon dioxide gas recovery apparatus 400 configured as described above will be described. Here, the flow of the heat medium of the heat pump 6 will be described starting from the heat medium expansion turbine 406.

  The heat medium whose temperature has been lowered by the heat medium expansion turbine 406 passes through the main pipe 404 and then is branched by the heat medium distributor 109 and is heated in each heat exchanger through the three branch pipes 405. They merge at the medium collector 110. The heat medium merged in the heat medium collector 110 is heated by the heat medium compressor 42 through the main pipe 404, and then heat-exchanged with the absorption liquid on the reboiler system 19 side in the heat medium reboiler heater 403. Thus, the heat of the heat medium is transferred to the absorbing liquid and heated. Then, it moves toward the heat medium distributor 109 through the main pipe 404. At this time, the temperature of the heat medium is lowered again by the heat medium expansion turbine 406.

As described above, according to the carbon dioxide gas recovery apparatus 400 according to the present embodiment, since the heat medium reboiler heater 403 is interposed between the reboiler system 19 and the heat pump 6, the reboiler system 19 side. By exchanging heat between the absorption liquid and the heat medium on the heat pump 6 side, the heat of the heat medium can be received by the absorption liquid and the absorption liquid can be heated.
As a result, the amount of heat input from the outside in the reboiler system 19 can be further suppressed, and further energy saving can be achieved.
Although the heat pump 6 is not provided with the regeneration tower internal heat exchange 38, it may be provided.

(Sixth embodiment)
Next, a carbon dioxide gas recovery device according to a sixth embodiment of the present invention will be described.
In the sixth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different points will be described.

As shown in FIG. 6, the heat pump 6 is not provided in the carbon dioxide gas recovery device 500 of the present embodiment.
Further, the absorption tower packing 8 is disposed in the tower middle part 2c of the absorption tower 2 in an upper and lower part, and the lean absorption liquid is led to the absorption tower 2 from the tower middle part 2c of the absorption tower 2. After cooling, an intercooler system 501 is provided that is reintroduced from the tower middle portion 2c.
The lean supply passage 5 is provided with a lean amine cooler 502 for cooling the lean absorbing liquid on the downstream side of the amine heat exchanger 36.

The piping 29 of the mixed gas cooling system 20 is not provided with the decompression / expansion valve 31, and the condensate circulation is provided between the gas-liquid separator 32 and the fourth nozzle 28 in the piping 29. A level adjustment valve 503 is provided instead of the pump 29a.
The gas-liquid separator 32 includes a condensate that is the vapor of the solute and the solvent condensed by the condensation heat exchanger 34, and the remaining uncondensed gas that is composed of the vapor of the solute and the solvent and the carbon dioxide gas. The temperature rising mixed gas is separated. The gas-liquid separator 32 is provided with a residual gas flow passage 504 connected to the tower top 3 b of the regeneration tower 3 through another gas-liquid separator 505 described later, instead of the discharge passage 33.

In the remaining gas flow passage 504, the remaining non-condensed heated mixture gas separated by the gas-liquid separator 32 passes. In the residual gas flow passage 504, a third rich amine heat exchanger (second heat exchanger) 514, the pressure reduction / expansion valve 31, the condensate of the vapors of the solute and the solvent, and uncondensed carbon dioxide are described. Another gas-liquid separator 505 for separating gas and a level control valve 506 are arranged in this order from the gas-liquid separator 32 to the top 3b of the regeneration tower 3.
The other gas-liquid separator 505 is provided with the discharge path 33.

  Further, a rich amine distributor 507 for branching the flow of the rich absorbent liquid and a branched rich absorbent liquid circulate in a portion located between the absorption tower bottom pump 17 and the amine heat exchanger 36 in the rich supply path 4. Three rich branch paths 508, 509, 510 and a rich amine collector 511 into which the rich branch paths 508, 509, 510 merge.

Between the first rich branch 508 of the three rich branches 508, 509, and 510 and the lean supply path 5, the first rich amine heat exchange that exchanges heat between the rich absorbent and the lean absorbent. 512 is interposed. The first rich amine heat exchanger 512 is interposed downstream of the amine heat exchanger 36 in the lean supply path 5.
Further, between the second rich branch 509 of the three rich branches 508, 509, and 510 and the reboiler pipe 26, the second rich amine heat that exchanges heat between the rich absorbent and the high-temperature fluid. Intersection 513 is interposed. The second rich amine heat exchanger 513 is interposed downstream of the steam trap 27 in the reboiler pipe 26.

In this embodiment, between the mixed gas cooling system 20 and the rich supply path 4, the third rich amine heat that exchanges heat between the temperature rising mixed gas after passing through the condensation heat exchanger 34 and the rich absorbing liquid. Intersection 514 is interposed.
The third rich amine heat exchanger 514 is interposed in the third rich branch 510 of the three rich branches 508, 509, 510, and upstream of the pressure reducing / expansion valve 31 in the residual gas flow passage 504. It is installed on the side.

Next, the operation of the carbon dioxide gas recovery apparatus 500 configured as described above will be described.
First, the flow of the rich absorbent in the rich supply path 4 will be described.
The rich absorbent passing through the rich supply path 4 reaches the rich amine distributor 507 and then branches into three branch paths 508, 509, and 510.

Among these, the rich absorption liquid passing through the first rich branch 508 is heated while cooling the lean absorption liquid by exchanging heat with the lean absorption liquid on the lean supply path 5 side in the first rich amine heat exchange 512. The
Further, the rich absorbent passing through the second rich branch 509 is heated by receiving heat from the high-temperature fluid by exchanging heat with the high-temperature fluid in the reboiler pipe 26 in the second rich amine heat exchange 513.
Further, the rich absorbing liquid passing through the third rich branch 510 is exchanged with the remaining temperature rising mixed gas flowing through the remaining gas flow passage 504 in the third rich amine heat exchange 514, whereby the remaining rising temperature is increased. The hot mixed gas is heated while cooling.

  Then, the rich absorbent heated through the rich branch paths 508, 509, and 510 is joined by the rich amine collector 511 and then supplied to the third nozzle 16.

Next, the flow of the mixed gas in the mixed gas cooling system 20 will be described.
The mixed gas that has risen in the regeneration tower 3 passes through the pipe 29 of the mixed gas cooling system 20 and is first compressed by the mixed gas compressor 30 to be heated to become a heated mixed gas. Thereafter, the condensation heat exchanger 34 performs heat exchange with the absorption liquid on the reboiler system 19 side, thereby recovering the latent heat of the solute and the solvent vapor, and condensing at least a part of the solute and the solvent vapor. It becomes a condensate.
Next, the condensate is separated from the remaining non-condensed temperature rising mixed gas by the gas-liquid separator 32, and among these, the condensate passes through the pipe 29 to the tower top 3 b of the regeneration tower 3. Supplied from the fourth nozzle 28.

  On the other hand, the uncondensed remaining temperature rising mixed gas passes through the residual gas flow passage 504 and exchanges heat with the rich absorption liquid passing through the third rich branch 510 in the third rich amine heat exchanger 514, The sensible heat and the latent heat of the remaining steam are recovered. That is, the latent heat of the vapor of the solute and the solvent is recovered to condense the vapor of the solute and the solvent in the remaining temperature rising mixed gas, and the carbon dioxide gas in the remaining temperature rising mixed gas Sensible heat is recovered. Thereafter, the remaining temperature rising mixed gas is expanded by the pressure reduction / expansion valve 31 and the temperature is lowered, so that all the vapor components of the solute and the solvent in the remaining temperature rising mixed gas are condensed and condensed liquid and Become.

  Then, the condensate and uncondensed carbon dioxide gas are separated by another gas-liquid separator 505, and among these, the condensate passes through the residual gas flow passage 504 and is the top of the regeneration tower 3. While being supplied to 3 b, the carbon dioxide gas is discharged through the discharge path 33.

  As described above, according to the carbon dioxide gas recovery device 500 according to the present embodiment, the third rich amine heat exchange 514 is interposed between the mixed gas cooling system 20 and the rich supply path 4. , By exchanging heat between the remaining temperature rising mixed gas on the mixed gas cooling system 20 side and the rich absorbent on the rich supply path 4 side, while heating the rich absorbent supplied to the regeneration tower 3, The remaining temperature rising mixed gas can be cooled.

  In this way, the rich absorption liquid supplied to the regeneration tower 3 can be preheated by the amount of heat of the mixed gas flowing out of the regeneration tower 3, so the amount of heat that the rich absorption liquid needs to receive in the regeneration tower 3. Can be suppressed. Therefore, the amount of heat input from the outside in the reboiler system 19 can be further suppressed, and further energy saving can be achieved.

  Further, since the temperature rising mixed gas on the mixed gas cooling system 20 side passes through the condensation heat exchanger 34 and then passes through the third rich amine heat exchanger 514, the vapor content of the solute and the solvent in the temperature rising mixed gas. After the latent heat is recovered by the condensing heat exchanger 34, the sensible heat of the remaining unheated mixed gas mixture and the remaining latent heat can be recovered by the third rich amine heat exchanger 514.

Here, as in the first embodiment, the above effects are generalized and described. In this embodiment, (1) the self-heat regeneration effect of reaction heat and (2) self-heat of latent heat required for tower operation are described. In addition to playback, the following one item can be described.
(3) Self-thermal regeneration of sensible heat required for tower operation The amount of sensible heat corresponding to CO ₂ contained in the rich absorbent flowing into the regeneration tower 3 is equal to the gas sensible heat of the remaining temperature rising mixed gas. Therefore, if the temperature rising mixed gas is obtained with a slight power for compressing the mixed gas and the sensible heat is recovered by the third rich amine heat exchange 514, the preheating amount of the rich absorbent introduced into the regeneration tower increases. Thus, the amount of heat to be applied from the outside in the reboiler system 19 is reduced. Strictly speaking, the amount of heat to be applied is the amount of recovery leakage heat in the amine heat exchanger 36 (the sensible heat amount of the lean absorbing liquid flowing out of the amine heat exchanger 36 and the sensible heat amount of the rich absorbing liquid flowing in the amine heat exchanger 36). The sum of the amount of heat excluding the sensible heat equivalent of CO ₂ contained in the rich absorbent from the difference) and the amount of heat commensurate with the amount of heat released around the regeneration tower 3.
Furthermore, if the heat transfer area of the amine heat exchanger 36 is set to be large and the amount of heat leaked from the amine heat exchanger 36 is brought close to zero, the amount of heat to be applied from the outside in the reboiler system 19 is the amount of heat that only corresponds to the amount of heat released around the regeneration tower 3. Therefore, the amount of heat to be finally applied from the outside in the reboiler system 19 can be made near zero.

In the present embodiment, in the third rich amine heat exchanger 514, heat exchange is performed between the remaining temperature rising mixed gas on the mixed gas cooling system 20 side and the rich absorbent on the rich supply path 4 side. However, it is not limited to this. For example, in the third rich amine heat exchanger 514, heat exchange may be performed between the carbon dioxide gas and the rich absorbing solution, and sensible heat recovery of the carbon dioxide gas may be performed. In this case, for example, in the gas-liquid separator 32, the solute and the vapor of the solvent in the temperature rising mixed gas are all separated from the carbon dioxide gas at the upstream side of the gas-liquid separator 32. The mixed gas cooling system 20 may be configured so that all of the vapors of the solute and the solvent in the warm mixed gas are condensed.
In the present embodiment, the heat pump 6 is not provided, but the heat pump 6 may be provided.

(Seventh embodiment)
Next, a carbon dioxide gas recovery device according to a seventh embodiment of the present invention will be described.
Note that in the seventh embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different points will be described.

As shown in FIG. 7, in the carbon dioxide gas recovery device 600 of the present embodiment, the rich amine distribution that branches the flow of the rich absorbent into the portion located downstream of the absorption tower bottom pump 17 in the rich supply path 4. 601, two rich branch paths 602 and 603 through which the branched rich absorption liquid flows, and a rich amine collector 604 in which the rich branch paths 602 and 603 merge.
Of the two rich branch paths 602 and 603, the amine heat exchanger 36 is interposed between one rich branch path 602 and the lean supply path 5.

  The heat pump 6 does not include the regeneration tower internal heat exchange 38. In this embodiment, between the rich supply path 4 and the heat pump 6, the first rich amine heat exchange (13th heat) exchanges heat between the rich absorbing liquid and the heat medium that has been compressed and raised in temperature. (Exchanger) 605 is interposed.

  In the illustrated example, the heat pump 6 includes a heat pump pipe 607 that connects the lower side and the upper side of the heat exchange 37 inside the absorption tower. The heat pump pipe 607 is provided with the heat medium compressor 42, and a heat medium expansion turbine 608 that lowers the temperature by expanding the heat medium is provided downstream of the heat medium compressor 42 in the heat pump pipe 607. ing. The heat medium expansion turbine 608 obtains rotational power when the heat medium is expanded.

  The first rich amine heat exchanger 605 is interposed downstream of the heat medium compressor 42 and upstream of the heat medium expansion turbine 608 in the heat pump pipe 607 and is rich in the rich supply path 4. It is interposed downstream from the amine collector 604.

  Further, the pressure reducing / expansion valve 31 of the mixed gas cooling system 20 is provided in the discharge passage 33, and condensate is provided between the gas-liquid separator 32 and the fourth nozzle 28 in the pipe 29 of the mixed gas cooling system 20. A level adjustment valve 609 is provided instead of the circulation pump 29a. Further, in the illustrated example, the condensation heat exchanger 34 is not provided.

  In the present embodiment, a second rich amine heat exchanger (third heat exchanger) 610 that exchanges heat between the temperature rising mixed gas and the rich absorbent is provided between the mixed gas cooling system 20 and the rich supply path 4. Intervene. Furthermore, between the mixed gas cooling system 20 and the rich supply path 4, a third rich amine heat exchange (which exchanges heat between the temperature-increased mixed gas and the rich absorbent after passing through the second rich amine heat exchange 610 ( A fourth heat exchanger) 611 is interposed.

In the illustrated example, the second rich amine heat exchanger 610 is interposed downstream of the mixed gas compressor 30 and upstream of the gas-liquid separator 32 in the piping 29 of the mixed gas cooling system 20. In the rich supply path 4, the rich supply path 4 is interposed downstream from the first rich amine heat exchanger 605.
The third rich amine heat exchanger 611 is interposed upstream of the pressure reduction / expansion valve 31 in the discharge passage 33 of the mixed gas cooling system 20, and two rich branch passages 602 and 603 in the rich supply passage 4. Of these, the other branch 603 different from one rich branch 602 is interposed.

Next, the operation of the carbon dioxide gas recovery apparatus 600 configured as described above will be described.
First, the flow of the rich absorbent in the rich supply path 4 will be described.
The rich absorbent passing through the rich supply path 4 reaches the rich amine distributor 601 and then branches into two rich branch paths 602 and 603.

Among these, the rich absorption liquid passing through one rich branch path 602 is heated while cooling the lean absorption liquid by exchanging heat with the lean absorption liquid on the lean supply path 5 side in the amine heat exchange 36.
Further, the rich absorbing liquid passing through the other rich branch passage 603 exchanges heat with the carbon dioxide main gas on the discharge passage 33 side of the mixed gas cooling system 20 in the third rich amine heat exchange 611, so that the carbon dioxide main gas. Receives heat from and is heated.

Then, the rich absorbent heated through the rich branch paths 602 and 603 merges in the rich amine collector 604, and then exchanges heat with the heat medium of the heat pump 6 in the first rich amine heat exchanger 605. Heat is received from the heat medium and heated. Thereafter, the rich absorbent is further heated by cooling the heated mixed gas by exchanging heat with the heated mixed gas on the discharge path 33 side of the mixed gas cooling system 20 in the second rich amine heat exchanger 610.
The rich absorbent heated as described above is then supplied to the third nozzle 16.

Next, the flow of the mixed gas in the mixed gas cooling system 20 will be described.
The mixed gas that has risen in the regeneration tower 3 passes through the pipe 29 of the mixed gas cooling system 20 and is first compressed by the mixed gas compressor 30 to be heated to become a heated mixed gas. Thereafter, in the second rich amine heat exchanger 610, heat exchange with the rich absorption liquid on the rich supply path 4 side is performed to recover the latent heat of the solute and solvent vapor, and the solute and solvent vapor are condensed. It becomes a condensate.

  Subsequently, the condensate and the non-condensed carbon dioxide main gas mainly composed of carbon dioxide gas are separated by the gas-liquid separator 32, and among these, the condensate passes through the pipe 29 and enters the regeneration tower 3. The fourth nozzle 28 is supplied to the tower top 3b.

  On the other hand, the uncondensed carbon dioxide main gas passes through the discharge path 33, and in the third rich amine heat exchange 611, exchanges heat with the rich absorption liquid that passes through the one rich branch path 602, so that the sensible heat of the gas and After the latent heat of a part of the remaining steam is recovered, it is expanded by the pressure reduction / expansion valve 31 and the temperature is lowered and discharged. At this time, the latent heat of the vapor of the solute and the solvent is recovered to condense the vapor of the solute and the solvent in the carbon dioxide main gas, and the sensible heat of the carbon dioxide gas in the carbon dioxide main gas Collected.

Next, the flow of the heat medium in the heat pump 6 will be described starting from the heat medium expansion turbine 608.
The heat medium whose temperature is lowered by the heat medium expansion turbine 608 passes through the heat pump pipe 607 and then exchanges heat with the absorbing liquid while moving from the lower side to the upper side of the heat exchange 37 inside the absorption tower. The heat of the exothermic reaction is received while cooling the absorbing solution.
Then, the heat medium is compressed by the heat medium compressor 42 through the heat pump pipe 607 and the temperature is raised, and then heat exchange with the rich absorption liquid is performed in the first rich amine heat exchange 605, thereby converting the rich absorption liquid. Cooling while heating. Thereafter, the heat medium moves through the heat pump pipe 607 toward the lower side of the heat exchange 37 inside the absorption tower. At this time, the temperature of the heat medium is lowered again by the heat medium expansion turbine 608.

  As described above, according to the carbon dioxide gas recovery device 600 according to the present embodiment, the mixed gas cooling system 20 includes the mixed gas compressor 30, so that heating is performed from the outside by applying a slight external power. Therefore, since the second rich amine heat exchanger 610 is interposed between the mixed gas cooling system 20 and the rich supply path 4, the mixed gas cooling system 20 side is provided. Heat exchange is performed between the temperature rising mixed gas and the rich absorbent on the rich supply path 4 side to heat the rich absorbent supplied to the regeneration tower 3 by the amount of heat of the mixed gas flowing out of the regeneration tower 3. Meanwhile, the temperature rising mixed gas can be cooled.

  Thus, since the rich absorption liquid supplied to the regeneration tower 3 can be preheated, the amount of heat that the rich absorption liquid needs to receive in the regeneration tower 3 can be suppressed. Therefore, the amount of heat input from the outside in the reboiler system 19 can be suppressed, and energy saving can be achieved.

  Further, since the second rich amine heat exchange 610 and the third rich amine heat exchange 611 are interposed between the mixed gas cooling system 20 and the rich supply path 4, the rich absorption supplied to the regeneration tower 3. The liquid can be preheated effectively, and the amount of heat that the rich absorbing liquid needs to receive in the regeneration tower 3 can be further suppressed. Therefore, the amount of heat input from the outside in the reboiler system 19 can be further suppressed, and further energy saving can be achieved.

  Moreover, since the temperature rising mixed gas on the mixed gas cooling system 20 side passes through the second rich amine heat exchange 610 and then the third rich amine heat exchange 611, for example, the solute and the solvent in the temperature rising mixed gas After the latent heat of the steam is recovered by the second rich amine heat exchanger 610, the sensible heat of the non-condensed carbon dioxide main gas and the remaining latent heat can be recovered by the third rich amine heat exchanger 611.

  In addition, since the first rich amine heat exchange 605 is interposed between the rich supply path 4 and the heat pump 6, heat is generated between the rich absorbent on the rich supply path 4 side and the heat medium on the heat pump 6 side. By exchanging, the heat of the heat medium can be received by the rich absorption liquid supplied to the regeneration tower 3 and the rich absorption liquid can be heated.

  Thus, since the rich absorption liquid supplied to the regeneration tower 3 can be preheated, the amount of heat that the rich absorption liquid needs to receive in the regeneration tower 3 can be suppressed. Therefore, the amount of heat input from the outside in the reboiler system 19 can be further suppressed, and further energy saving can be achieved.

  Further, as in the present embodiment, when the amine heat exchanger 36 is interposed between the lean supply path 5 and the rich supply path 4, the amount of heat for heating the rich absorbent is reduced by the amine heat exchanger 36, The amount of heat to be given to the absorbent by the reboiler system 19 can be further suppressed. Therefore, the amount of heat input from the outside in the reboiler system 19 can be further suppressed, and further energy saving can be achieved.

  In the present embodiment, the heat pump 6 is not provided with the regeneration tower internal heat exchange 38, but may be provided. In the present embodiment, the condensation heat exchanger 34 is not provided, but may be provided. Furthermore, although the third rich amine heat exchanger 611 is provided in the present embodiment, it may not be provided.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in each of the above embodiments, in the mixed gas cooling system 20, the temperature of the temperature rising mixed gas is decreased by the pressure reducing / expansion valve 31, but an expansion turbine may be employed instead. In this case, rotational power can be obtained when the temperature rising mixed gas is expanded.

In the first to fifth and seventh embodiments, the heat pump 6 is provided. However, the heat pump 6 may be omitted.
Further, in the first to sixth embodiments, the second rich amine heat exchanger 610 shown in the seventh embodiment is not provided, but may be provided.

  In addition, it is possible to appropriately replace the constituent elements in the embodiment with known constituent elements without departing from the spirit of the present invention, and the above-described modified examples may be appropriately combined.

1, 100, 200, 300, 400, 500, 600 Carbon dioxide gas recovery device 2 Absorption tower 2a Tower bottom 2b Tower top 2c Tower intermediate section 3 Regeneration tower 4 Rich supply path 5 Lean supply path 6 Heat pump 8 Absorption tower packing 9 Lead-out path 10 Decarbonation gas cleaning system 18 Regeneration tower packing 19 Reboiler system 20 Mixed gas cooling system 26 Reboiler piping 30 Mixed gas compressor (mixed gas compressor)
34 Condensation heat exchanger (first heat exchanger)
37 Absorption tower internal heat exchange (5th heat exchanger)
38 Heat exchange inside regeneration tower (sixth heat exchanger)
102 Carbon dioxide gas cooler (seventh heat exchanger)
103 Washing water cooler (8th heat exchanger)
104 Richamine heat exchanger (9th heat exchanger)
201, 501 Intercooler system 206 Heat medium cooled intercooler (10th heat exchanger)
207 Heat-medium cooled lean amine cooler (11th heat exchanger)
308, 403 Heating medium reboiler heater (12th heat exchanger)
309 2nd amine heat exchange (13th heat exchanger)
514 Third rich amine heat exchange (second heat exchanger)
605 1st rich amine heat exchange (13th heat exchanger)
610 Second rich amine heat exchange (third heat exchanger)
611 3rd amine heat exchange (4th heat exchanger)

Claims (14)

An absorption tower that introduces and contacts a gas to be separated containing carbon dioxide gas and a lean absorbing liquid, and absorbs the carbon dioxide gas in the gas to be separated into the absorbing liquid to generate a rich absorbing liquid;
The rich absorption liquid is supplied from the absorption tower, and a regeneration tower that regenerates the lean absorption liquid by heating the rich absorption liquid and separating the carbon dioxide gas.
In the regeneration tower,
A reboiler system for extracting and heating the absorbing liquid from the regeneration tower and reintroducing it into the regeneration tower;
The mixed gas of the carbon dioxide gas and the solute of the absorption liquid and the vapor of the solvent is led out from the regeneration tower and cooled, and the vapor of the solute and the solvent is condensed and reintroduced into the regeneration tower. A mixed gas cooling system for discharging the carbon dioxide gas;
A carbon dioxide gas recovery device provided with
The mixed gas cooling system includes a mixed gas compressor that compresses the mixed gas and raises the temperature to form a heated mixed gas,
A carbon dioxide gas recovery apparatus, wherein a first heat exchanger for exchanging heat between the absorbing liquid and the temperature rising mixed gas is interposed between the reboiler system and the mixed gas cooling system. The carbon dioxide gas recovery device according to claim 1,
A rich supply path for supplying the rich absorbent from the absorption tower to the regeneration tower;
Between the mixed gas cooling system and the rich supply path, there is a second heat exchanger that exchanges heat between the temperature rising mixed gas after passing through the first heat exchanger and the rich absorbent. A carbon dioxide gas recovery device. An absorption tower that introduces and contacts a gas to be separated containing carbon dioxide gas and a lean absorbing liquid, and absorbs the carbon dioxide gas in the gas to be separated into the absorbing liquid to generate a rich absorbing liquid;
The rich absorption liquid is supplied from the absorption tower, and a regeneration tower that regenerates the lean absorption liquid by heating the rich absorption liquid and separating the carbon dioxide gas.
In the regeneration tower,
A reboiler system for extracting and heating the absorbing liquid from the regeneration tower and reintroducing it into the regeneration tower;
The mixed gas of the carbon dioxide gas and the solute of the absorption liquid and the vapor of the solvent is led out from the regeneration tower and cooled, and the vapor of the solute and the solvent is condensed and reintroduced into the regeneration tower. A mixed gas cooling system for discharging the carbon dioxide gas;
A carbon dioxide gas recovery device provided with
A rich supply path for supplying the rich absorbent from the absorption tower to the regeneration tower;
The mixed gas cooling system includes a mixed gas compressor that compresses the mixed gas and raises the temperature to form a heated mixed gas,
A carbon dioxide gas recovery system is characterized in that a third heat exchanger for exchanging heat between the temperature rising mixed gas and the rich absorbent is interposed between the mixed gas cooling system and the rich supply path. apparatus. The carbon dioxide gas recovery device according to claim 3,
Between the mixed gas cooling system and the rich supply path, there is a fourth heat exchanger that exchanges heat between the temperature rising mixed gas after passing through the third heat exchanger and the rich absorbent. A carbon dioxide gas recovery device. The carbon dioxide gas recovery device according to any one of claims 1 to 4,
The heat generated by the exothermic reaction when the absorbing liquid absorbs the carbon dioxide gas in the absorption tower is moved through a heat medium, and the carbon dioxide gas is separated from the rich absorbing liquid in the regeneration tower. A carbon dioxide gas recovery apparatus comprising a heat pump used as a heat source for an endothermic reaction. The carbon dioxide gas recovery device according to claim 5,
The heat pump is interposed in an absorption tower packing disposed in the absorption tower, and exchanges heat between the heat medium that has been expanded and reduced in temperature and the absorption liquid in the absorption tower. 5. A carbon dioxide gas recovery apparatus comprising a 5 heat exchanger. The carbon dioxide gas recovery device according to claim 5 or 6,
The heat pump exchanges heat between the heat medium that is interposed in the regenerative tower packing disposed in the regenerative tower, is compressed, and has its temperature raised, and the rich absorbent in the regenerative tower. A carbon dioxide gas recovery device comprising a sixth heat exchanger. The carbon dioxide gas recovery device according to any one of claims 5 to 7,
The absorption tower is provided with a lead-out path for decarboxylating gas derived from the carbon dioxide gas separated from the gas to be separated,
A seventh heat exchanger for exchanging heat between the decarbonation gas and the expanded heat-reduced heat medium is interposed between the lead-out path and the heat pump. Carbon dioxide gas recovery device. The carbon dioxide gas recovery device according to any one of claims 5 to 8,
The absorption tower is provided with a decarbonation gas cleaning system for introducing the cleaning liquid stored at the top of the absorption tower from the absorption tower and cooling it, and then reintroducing it from the top of the absorption tower.
Between the decarbonation gas cleaning system and the heat pump, an eighth heat exchanger for exchanging heat between the cleaning liquid and the heat medium expanded and reduced in temperature is interposed. Carbon dioxide gas recovery device. The carbon dioxide gas recovery device according to any one of claims 5 to 9,
A rich supply path for supplying the rich absorbent from the absorption tower to the regeneration tower;
Between the rich supply path and the heat pump, a ninth heat exchanger for exchanging heat between the rich absorbent and the heat medium expanded and lowered in temperature is interposed. Carbon dioxide gas recovery device. The carbon dioxide gas recovery device according to any one of claims 5 to 10,
The absorption tower is provided with an intercooler system for introducing and cooling the absorption liquid from the tower intermediate portion between the tower top and the tower bottom in the absorption tower, and then reintroducing from the tower intermediate portion.
A tenth heat exchanger for exchanging heat between the absorbing liquid and the expanded heat-reduced heat medium is interposed between the intercooler system and the heat pump. Carbon gas recovery device. The carbon dioxide gas recovery device according to any one of claims 5 to 11,
A lean supply path for supplying the lean absorbing liquid from the regeneration tower to the absorption tower;
An eleventh heat exchanger is provided between the lean supply path and the heat pump to exchange heat between the lean absorbing liquid and the heat medium expanded and lowered in temperature. Carbon dioxide gas recovery device. The carbon dioxide gas recovery device according to any one of claims 5 to 12,
A twelfth heat exchanger is provided between the reboiler system and the heat pump, and a twelfth heat exchanger for exchanging heat between the absorbing liquid and the heat medium that has been compressed and the temperature is increased. Carbon gas recovery device. The carbon dioxide gas recovery device according to any one of claims 5 to 13,
A rich supply path for supplying the rich absorbent from the absorption tower to the regeneration tower;
A thirteenth heat exchanger is provided between the rich supply path and the heat pump to exchange heat between the rich absorbent and the heat medium compressed and temperature-increased. Carbon dioxide gas recovery device.

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