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EP-3928857-B1 - COOLING ABSORPTION TOWER, CO2 RECOVERY DEVICE COMPRISING SAME, AND CO2 RECOVERY METHOD

EP3928857B1EP 3928857 B1EP3928857 B1EP 3928857B1EP-3928857-B1

Inventors

  • SORIMACHI, YOSHIKI
  • KAMIJO, TAKASHI
  • KISHIMOTO, SHINYA

Dates

Publication Date
20260506
Application Date
20200210

Claims (6)

  1. A CO 2 recovery device (1), comprising a cooling absorption tower (2) including: an outer shell (4); a cooling section (6) for cooling a flue gas, the cooling section (6) being disposed in the outer shell (4); and an absorbing section (8) configured to cause CO 2 in the flue gas cooled by the cooling section (6) to be absorbed in an absorption solvent, the absorbing section (8) being disposed in the outer shell (4) and above the cooling section (6), wherein the absorbing section (8) includes a chimney tray (10, 10A, 10B) for storing the absorption solvent which has absorbed CO 2 in the flue gas, the chimney tray (10, 10A, 10B) being disposed at a lowest portion of the absorbing section (8), the CO 2 recovery device (1) being characterized in that it further comprises: an absorption solvent tank (66) disposed below the absorbing section (8); and a tank introduction line (68) for introducing the absorption solvent stored in the chimney tray (10, 10A, 10b) to the absorption solvent tank (66) wherein the tank introduction line (68) includes an overflow line (70) connected to the chimney tray (10) within a height range of an upper half of a riser (84) of the chimney tray (10, 10A, 10B), wherein the CO 2 recovery device comprises: a valve (72) disposed in the overflow line (70); and a blower (16) for feeding a flue gas to the cooling absorption tower (2), and wherein the valve (72) is configured to be opened based on a signal indicating that the blower (16) is stopped.
  2. The CO 2 recovery device according to claim 1, wherein an inner diameter (d C ) of the outer shell (4) at the cooling section (6) is larger than an inner diameter (d A ) of the outer shell (4) at the absorbing section (8).
  3. Use of the CO 2 recovery device according to claim 1 or 2, wherein the cooling absorption tower (2) is installed on a ground surface, and the tank introduction line (68) extends to the absorption solvent tank (66) only via ground surface.
  4. The CO 2 recovery device according to claim 1 or 2, comprising: a regeneration tower (12) for regenerating the absorption solvent from the absorbing section (8); a regeneration tower introduction line (26) for extracting the absorption solvent from the chimney tray (10, 10A, 10B) and introducing the absorption solvent to the regeneration tower (12); and a branch line (74) branching from the regeneration tower introduction line (26) and connected to the absorption solvent tank (66), wherein the tank introduction line (68) includes the branch line (74) and a portion of the regeneration tower introduction line (26) upstream of a branch position of the branch line (74).
  5. The CO 2 recovery device according to claim 4, further comprising an absorption solvent pump (28) for pumping the absorption solvent to the regeneration tower (12), the absorption solvent pump (28) being disposed in a portion of the regeneration tower introduction line (26) downstream of the branch position.
  6. A CO 2 recovery method, comprising: a step of cooling a flue gas by a cooling section (6) disposed in an outer shell (4); a step of feeding the flue gas cooled by the cooling section (6) to an absorbing section (8) disposed in the outer shell (4) and above the cooling section (6); a step of causing CO 2 in the flue gas to be absorbed in an absorption solvent by the absorbing section (8); a step of storing the absorption solvent which has absorbed CO 2 in the flue gas by the absorbing section (8) in a chimney tray (10, 10A, 10B) disposed at a lowest portion of the absorbing section (8); the CO 2 recovery method being characterized in that it further comprises: a step of introducing the absorption solvent stored in the chimney tray (10, 10A, 10B) to an absorption solvent tank (66) disposed below the absorbing section (8) via a tank introduction line (68), and a step of feeding a flue gas to the cooling section (6) by using a blower (16), wherein the cooling step includes cooling the flue gas fed by the blower (16), and wherein the step of introducing to the absorption solvent tank (66) includes, when the blower (16) is stopped, opening a valve (72) disposed in the tank introduction line (68) to introduce the absorption solvent to the absorption solvent tank (66).

Description

TECHNICAL FIELD The present disclosure relates to a cooling absorption tower, a CO2 recovery device including the same, and a CO2 recovery method. BACKGROUND As a method for recovering CO2 in flue gas produced by combustion of fuel or the like, a method has been proposed in which the flue gas and a CO2 absorption solvent are brought into gas-liquid contact to recover CO2 in the flue gas. For example, Japanese patent application JP2013-59726A discloses a CO2 recovery device including a cooling tower, an absorption tower, and a regeneration tower. In this CO2 recovery device, CO2-containing flue gas is first cooled in the cooling tower, and then the CO2-containing gas is brought into contact with an absorption solvent in the absorption tower such that CO2 is absorbed by the absorption solvent to remove CO2 from the gas. The absorption solvent (rich solvent) which has absorbed CO2 in the absorption tower is introduced to the regeneration tower and then heated with steam in a regeneration reboiler to separate CO2 from the absorption solvent, and the separated CO2 is recovered. The absorption solvent (lean solution) regenerated in the regeneration tower is returned to the absorption tower to be reused as the CO2 absorption solvent. In addition, European patent application EP1962992 A2 discloses a flue gas treatment system comprising a quench section and a scrubbing section that are configured and operated to avoid net condensation of water from the quenched flue gas in the scrubbing section. In detail, such flue gas treatment system comprises a quench section, which is adapted to receive a flue gas at a first temperature and to cool the flue gas to a lower temperature using water; and a scrubbing section fluidly coupled to the quench section, which is adapted to contact the quenched flue gas with a caustic solvent. Similar arrangements are disclosed for instance in the German patent application DE3738913 A1. SUMMARY Problems to be Solved In the CO2 recovery device described in Patent Document 1, the cooling tower and the absorption tower are composed of separate outer shells (towers), and these outer shells are connected to each other by a connection duct. In this configuration, since the cooling tower and the absorption tower are installed separately, and an area is needed for the connection duct between the cooling tower and the absorption tower, the installation area is increased. In particular, the connection duct between the cooling tower and the absorption tower needs to be routed from the top of the cooling tower to the bottom of the absorption tower, which is a major factor in increasing the installation area of the CO2 recovery device. Therefore, it is desirable to reduce the installation area of the CO2 recovery device. In view of the above, an object of at least one embodiment of the present invention is to provide a cooling absorption tower, a CO2 recovery device including the same, and a CO2 recovery method whereby it is possible to reduce the installation area of the equipment. Solution to the Problems The present invention is relative to a CO2 recovery device and to a CO2 recovery method as claimed in the appended set of claims. According to the claimed invention, since the cooling section and the absorbing section disposed above the cooling section are installed in one outer shell, the flue gas can be treated by the cooling section and then be raised and treated by the absorbing section in one outer shell. In other words, according to the claimed invention, the functions of both the cooling tower and the absorption tower can be contained in one outer shell. Thus, compared to the case where the cooling tower and the absorption tower are installed separately, the installation space for outer shells (towers) and a connection duct connecting the outer shells can be reduced, so that the installation area of the equipment can be reduced. In addition, since the necessity of the connection duct and its support member is eliminated, costs such as material and production costs can be reduced. In addition, since the chimney tray for holding the absorption solvent used in the absorbing section is disposed at the lowest portion of the absorbing section, the absorption solvent is prevented from dropping into the cooling section disposed below the absorbing section. Thus, while appropriately preventing mixing of the absorption solvent into cooling water used in the cooling section, the functions of both the cooling tower and the absorption tower can be contained in one outer shell, as described in the above (1). According to the claimed invention, since the inner diameter of the outer shell at the absorbing section is set to be smaller than the inner diameter of the outer shell at the cooling section, the material cost for manufacturing the cooling absorption tower can be reduced compared to the case where the inner diameter at the absorbing section is the same as the inner diameter at the cooling section. Sinc