[0001] The present disclosure relates to an absorption solvent regeneration device, a
CO2 recovery device, and a method for modifying an absorption solvent regeneration
device.
5 BACKGROUND
[0002] 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.
[0003] For example, Patent Document 1 discloses a CO2 recovery device including
10 an absorber and a regenerator. In the absorber, a CO2-containing gas and an absorption
solvent are brought into contact 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 absorber is introduced to the regenerator and then heated with steam in a
regeneration reboiler to remove CO2 from the absorption solvent. The absorption
15 solvent (lean solution) thus regenerated is returned to the absorber to be reused as the CO2
absorption solvent.
[0004] Further, Patent Document 1 describes that part of the absorption solvent (rich
solvent) from the absorber to the regenerator is branched, and the branched absorption
solvent is heated by residual heat of steam condensate from the regeneration reboiler and
20 then introduced to the regenerator. By using the residual heat of steam condensate used
in the regeneration reboiler to heat the absorption solvent, the steam consumption
required for regeneration of the absorption solvent (i.e., steam consumption in the
regeneration reboiler) is reduced.
Citation List
25 Patent Literature
[0005] Patent Document 1: JP2005-254212A
3
SUMMARY
Problems to be Solved
[0006] The absorption solvent heated in the regeneration reboiler (reboiler) for
regenerating the absorption solvent introduced to the regenerator is generally returned
from the regeneration reboiler to the regenerator 5 via a reboiler outlet line. Here,
depending on the flow state of the absorption solvent in the reboiler outlet line, vibration
may occur in a pipe that constitutes the reboiler outlet line.
In this regard, Patent Document 1 does not describe any countermeasures against
vibration that may occur in the reboiler outlet line.
10 [0007] In view of the above, an object of at least one embodiment of the present
invention is to provide an absorption solvent regeneration device, a CO2 recovery device,
and a method for modifying an absorption solvent regeneration device whereby it is
possible to suppress vibration or the like of a pipe in the reboiler outlet line while reducing
the consumption amount of a heating medium in the regeneration reboiler.
15
Solution to the Problems
[0008] (1) An absorption solvent regeneration device according to at least one
embodiment of the present invention comprises: a regenerator for regenerating an
absorption solvent by separating CO2 from the absorption solvent which has absorbed
20 CO2; a main rich solvent line for supplying the absorption solvent which has absorbed
CO2 to the regenerator; a regeneration reboiler for heating an absorption solvent extracted
from the regenerator; a reboiler line configured to extract the absorption solvent stored in
the regenerator and return the absorption solvent to the regenerator via the regeneration
reboiler; a branch rich solvent line branching from the main rich solvent line and
25 connected to a portion of the reboiler line downstream of the regeneration reboiler; and a
heating part for heating the absorption solvent flowing through the branch rich solvent
line, the heating part being disposed on the branch rich solvent line.
4
[0009] With the above configuration (1), the absorption solvent (rich solvent)
branching from the main rich solvent line is first heated by the heating part disposed on
the branch rich solvent line, and is then supplied to a portion (reboiler outlet line) of the
reboiler line downstream of the regeneration reboiler (reboiler). As a result, compared
to the case where the absorption solvent in 5 the main rich solvent line is not branched, the
amount of heat required to heat the absorption solvent in the regeneration reboiler can be
reduced, i.e., the amount of the heating medium consumed in the regeneration reboiler
can be reduced, and the piping vibration can be suppressed by adjusting the flow state in
the reboiler outlet line.
10 Further, with the above configuration (1), since the branch rich solvent line is
connected to the reboiler line, for example, compared to the case where the branch rich
solvent line is connected to the regenerator to reduce the consumption amount of the
heating medium in the regeneration reboiler, the cost of modifying the existing absorption
solvent regeneration device can be reduced, or the construction period can be shortened.
15 [0010] (2) In some embodiments, in the above configuration (1), the regeneration
reboiler is configured such that a flow of the absorption solvent discharged from the
regeneration reboiler to the reboiler line is a two-phase flow.
[0011] When the flow of the absorption solvent discharged from the regeneration
reboiler to the reboiler outlet line (reboiler line) is a two-phase flow, depending on the
20 operating condition of the absorption solvent regeneration device, the flow state of the
two-phase flow may be a bulk flow (slug flow) including a bulk liquid phase portion. In
this case, due to the bulk flow, vibration or the like may occur in a pipe that constitutes
the reboiler outlet line. In this regard, with the above configuration (2), even in the
operating condition where the two-phase flow is a bulk flow in the reboiler outlet line,
25 since the absorption solvent is supplied to the reboiler outlet line from the branch rich
solvent line connected to the reboiler outlet line, the flow rate in the reboiler outlet line
can be increased. Therefore, the flow state of the two-phase flow in the reboiler outlet
5
line is more likely to be an annular flow, which can suppress vibration of the pipe caused
by the bulk flow in the reboiler outlet line.
[0012] (3) In some embodiments, in the above configuration (1) or (2), the absorption
solvent regeneration device further comprises a steam supply line for supplying steam for
heating the absorption solvent to the regeneration 5 reboiler. The heating part includes a
heat exchanger configured to exchange heat between condensed water of steam after
heating the absorption solvent in the regeneration reboiler and the absorption solvent
flowing through the branch rich solvent line.
[0013] With the above configuration (3), since the absorption solvent in the branch
10 rich solvent line is heated by using excess heat of steam used in heating the absorption
solvent in the regeneration reboiler, compared to the case where the absorption solvent in
the main rich solvent line is not branched, the steam consumption amount in the
regeneration reboiler can be reduced, and the operating efficiency of the absorption
solvent regeneration device can be improved as a whole.
15 [0014] (4) In some embodiments, in any one of the above configurations (1) to (3),
the absorption solvent regeneration device further comprises a valve for regulating a flow
rate of the absorption solvent in the branch rich solvent line, the valve being disposed in
the branch rich solvent line.
[0015] With the above configuration (4), by regulating the flow rate of the absorption
20 solvent in the branch rich solvent line with the valve disposed in the branch rich solvent
line, the flow rate in the reboiler outlet line connected with the branch rich solvent line
can be regulated. This makes it easier to regulate the flow state in the reboiler outlet
line.
[0016] (5) A CO2 recovery device according to at least one embodiment of the present
25 invention comprises: an absorber configured to cause CO2 in a flue gas to be absorbed by
an absorption solvent by bringing the flue gas containing CO2 and the absorption solvent
into contact; and the absorption solvent regeneration device described in any one of the
6
above (1) to (4). The main rich solvent line is configured to supply the absorption
solvent which has absorbed CO2 in the absorber to the regenerator.
[0017] With the above configuration (5), the absorption solvent (rich solvent)
branching from the main rich solvent line is first heated by the heating part disposed on
the branch rich solvent line, and is then supplied to 5 a portion (reboiler outlet line) of the
reboiler line downstream of the regeneration reboiler. As a result, compared to the case
where the absorption solvent in the main rich solvent line is not branched, the amount of
heat required to heat the absorption solvent in the regeneration reboiler can be reduced,
i.e., the amount of the heating medium consumed in the regeneration reboiler can be
10 reduced, and the piping vibration can be suppressed by adjusting the flow state in the
reboiler outlet line.
Further, with the above configuration (5), since the branch rich solvent line is
connected to the reboiler line, for example, compared to the case where the branch rich
solvent line is connected to the regenerator to reduce the consumption amount of the
15 heating medium in the regeneration reboiler, the cost of modifying the existing absorption
solvent regeneration device can be reduced, or the construction period can be shortened.
[0018] (6) A method for modifying an absorption solvent regeneration device
according to at least one embodiment of the present invention is a method for modifying
an absorption solvent regeneration device including: a regenerator for regenerating an
20 absorption solvent by separating CO2 from the absorption solvent which has absorbed
CO2; a main rich solvent line for supplying the absorption solvent which has absorbed
CO2 to the regenerator; a regeneration reboiler for heating an absorption solvent extracted
from the regenerator; and a reboiler line configured to extract the absorption solvent
stored in the regenerator and return the absorption solvent to the regenerator via the
25 regeneration reboiler, and the method comprises a step of additionally installing a branch
rich solvent line branching from the main rich solvent line and connected to a portion of
the reboiler line downstream of the regeneration reboiler, and a heating part for heating
7
the absorption solvent flowing through the branch rich solvent line, the heating part being
disposed in the branch rich solvent line.
[0019] With the above modifying method (6), by connecting the branch rich solvent
line to the reboiler outlet line (reboiler line), the absorption solvent regeneration device
(1) can be obtained. Therefore, unlike 5 the case described in Patent Document 1, for
example, where the branch rich solvent line is connected to the regenerator in order to
reduce the consumption amount of the heating medium (e.g., steam) in the regeneration
reboiler, no construction of the regenerator is required. Thus, for obtaining the
absorption solvent regeneration device that can reduce the consumption amount of the
10 heating medium in the regeneration reboiler, the cost of modifying the existing absorption
solvent regeneration device can be reduced, or the construction period can be shortened.
Further, in the absorption solvent regeneration device obtained with the modifying
method (6), the absorption solvent (rich solvent) branching from the main rich solvent
line is supplied to a portion (reboiler outlet line) of the reboiler line downstream of the
15 regeneration reboiler. Accordingly, vibration of the pipe can be suppressed by adjusting
the flow state in the reboiler outlet line.
[0020] (7) In some embodiments, the above method (6) further comprises a step of
installing, in the branch rich solvent line, a valve for regulating a flow rate of the
absorption solvent in the branch rich solvent line.
20 [0021] When the valve is installed in the branch rich solvent line with the above
method (7), the flow rate of the absorption solvent in the branch rich solvent line can be
regulated by appropriately operating the valve. This enables the regulation of the flow
rate in the reboiler outlet line connected to the branch rich solvent line, making it easier
to regulate the flow state in the reboiler outlet line.
25
Advantageous Effects
[0022] At least one embodiment of the present invention provides an absorption
8
solvent regeneration device, a CO2 recovery device, and a method for modifying an
absorption solvent regeneration device whereby it is possible to suppress vibration or the
like of a pipe in the reboiler outlet line while reducing the consumption amount of a
heating medium in the regeneration reboiler.
5 BRIEF DESCRIPTION OF DRAWINGS
[0023] FIG. 1 is a schematic diagram of a CO2 recovery device including an
absorption solvent regeneration device according to an embodiment.
FIG. 2 is a schematic diagram showing a connection portion between a branch rich
solvent line and a reboiler outlet line in an absorption solvent regeneration device
10 according to an embodiment.
FIG. 3 is a schematic diagram showing a connection portion between a branch rich
solvent line and a reboiler outlet line in an absorption solvent regeneration device
according to an embodiment.
15 DETAILED DESCRIPTION
[0024] Embodiments of the present invention will now be described in detail with
reference to the accompanying drawings. It is intended, however, that unless
particularly identified, dimensions, materials, shapes, relative positions, and the like of
components described in the embodiments shall be interpreted as illustrative only and not
20 intended to limit the scope of the present invention.
[0025] FIG. 1 is a schematic diagram of a CO2 recovery device including an
absorption solvent regeneration device according to an embodiment of the present
invention. The CO2 recovery device 1 shown in FIG. 1 is a device for recovering CO2
from flue gas discharged from a power generation facility, a plant, or the like. As
25 illustrated in the drawing, the CO2 recovery device 1 includes an absorber 2 for causing
CO2 in the flue gas to be absorbed in an absorption solvent, and an absorption solvent
regeneration device 4 including a regenerator 6 for regenerating the absorption solvent
9
which has absorbed CO2 in the absorber 2. The absorption solvent regeneration device
4 includes a main rich solvent line 10 disposed between the absorber 2 and the regenerator
6, and a regeneration reboiler (reboiler) 24 for heating the absorption solvent stored in the
regenerator 6.
[0026] Flue gas from a plant or the like is introduced 5 to the absorber 2 via a flue gas
introduction line 8. Flue gas from a plant or the like may be introduced to the absorber
2 after pre-treatment such as sulfur removal and cooling.
[0027] The absorber 2 includes an absorbing section 32 for absorbing CO2 gas in the
flue gas, a washing section 34 for washing the flue gas from which the CO2 gas has been
10 removed, and a demister 40, disposed above the washing section 34, for removing mist
in the flue gas.
[0028] The absorbing section 32 is supplied with the absorption solvent (lean solvent)
stored in the tower bottom portion of the regenerator 6 via a lean solvent line 16. The
lean solvent line 16 is provided with a lean solvent pump 17 for pumping the lean solvent.
15 The flue gas entering the absorber 2 through the flue gas introduction line 8 flows upward
in the absorber 2 from the bottom portion side of the absorber 2, flows into the absorbing
section 32, and comes into countercurrent contact in the absorbing section 32 with the
absorption solvent (lean solvent) supplied from above the absorbing section 32. As a
result, CO2 in the flue gas is absorbed by the absorption solvent, and CO2 is separated and
20 removed from the flue gas. The absorbing section 32 may be formed by a packed layer
packed with a packing material made of any material.
[0029] The absorption solvent is a liquid containing a CO2 absorption agent.
Although the type of CO2 absorption agent is not limited, amines such as alkanolamines
represented by monoethanolamine and diethanolamine, and various alkaline solutions
25 other than amines such as sodium hydroxide, potassium hydroxide, and calcium
hydroxide can be used as the CO2 absorption agent.
[0030] The absorption solvent which has absorbed CO2 from the flue gas in the
10
absorbing section 32 descends to the bottom portion of the absorber 2 and is stored in the
tower bottom portion. The absorption solvent stored in the bottom portion of the
absorber 2 is a rich solvent having a higher CO2 concentration than the absorption solvent
(lean solvent) stored in the bottom portion of the regenerator 6.
[0031] The washing section 34 i 5 s configured to wash the flue gas in order to recover
the CO2 absorption agent contained in the flue gas after removal of CO2. The washing
section 34 is supplied with washing water from a circulation line 38 from above. When
the flue gas after removal of CO2 comes into contact with the washing water in the
washing section 34, the CO2 recovery agent contained in the flue gas is dissolved in the
10 washing water and thus can be recovered. Below the washing section 34, a chimney
tray 36 is disposed. The washing water which has descended from the washing section
34 is circulated through the circulation line 38 by a circulation pump 39 and is again
supplied to the washing section 34 from above the washing section 34.
[0032] The flue gas from which the CO2 absorption agent has been removed passes
15 through the demister 40 disposed above the washing section 34, where the mist in the flue
gas is captured. The flue gas deprived of mist is discharged outside from the tower top
portion 42 of the absorber 2.
[0033] The absorption solvent (rich solvent) stored in the bottom portion of the
absorber 2 is supplied from the absorber 2 to the regenerator 6 via a main rich solvent line
20 10. The main rich solvent line 10 is provided with a rich solvent pump 11 for pumping
the rich solvent from the bottom portion of the absorber 2 to the regenerator 6. Further,
a heat exchanger 18 is disposed in the main rich solvent line 10 to exchange heat between
the rich solvent flowing in the main rich solvent line 10 and the absorption solvent (lean
solvent) flowing in a lean solvent line 16, which will be described later. By heating the
25 rich solvent through heat exchange with the lean solvent of relatively high temperature in
the heat exchanger 18, it is possible to promote the regeneration of the absorption solvent
in the regenerator 6 described below.
11
[0034] The regenerator 6 includes a release section 44 for releasing CO2 gas from the
rich solvent, and a chimney tray 46 disposed below the release section 44. The release
section 44 has a packing material and is supplied with the absorption solvent (rich solvent)
from the main rich solvent line 10 from above. In the release section 44, the rich solvent
supplied as described above is heated by saturated 5 steam supplied from a regeneration
reboiler 24 to release the CO2 gas, so that the absorption solvent (lean solvent) with
relatively low CO2 content is obtained. The lean solvent that drops from the release
section 44 is received by the chimney tray 46.
[0035] The CO2 gas released from the rich solvent in the release section 44 rises
10 upward in the regenerator 6 toward the top of the release section 44, and after mist in the
gas is captured by a demister 48, the gas is discharged from the regenerator 6 through a
recovery line 28 connected to the top portion of the regenerator 6. The recovery line 28
is provided with a condenser 30. The condenser 30 is configured to cool the CO2 gas
discharged from the regenerator 6 by heat exchange with cooling water to condense
15 moisture contained in the CO2 gas. The CO2 gas thus separated from moisture is
recovered as a product. A gas-liquid separator (not shown) may be disposed
downstream of the condenser 30 in the recovery line 28 to separate the CO2 gas from the
condensate.
[0036] The regenerator 6 is connected to a reboiler line 20 with a regeneration
20 reboiler 24. The reboiler line 20 is configured to extract the absorption solvent stored
in the regenerator 6 and return it to the regenerator 6 via the regeneration reboiler 24.
The regeneration reboiler 24 is configured to heat the absorption solvent (lean solvent)
introduced through the reboiler line 20, by heat exchange with a heating medium. In the
exemplary embodiment shown in FIG. 1, the regeneration reboiler 24 is supplied with
25 steam as the heating medium via a steam supply line 22.
[0037] The lean solvent received by the chimney tray 46 in the regenerator 6 is
extracted from the regenerator 6 via a reboiler inlet line 20a of the reboiler line 20 and is
12
introduced to the regeneration reboiler 24. In the regeneration reboiler 24, the lean
solvent from the reboiler inlet line 20a is heated by heat exchange with steam from the
steam supply line 22.
[0038] The regeneration reboiler 24 may be configured such that the flow of the
absorption solvent (lean solvent) discharged from 5 the regeneration reboiler 24 to the
reboiler outlet line 20b (reboiler line 20) is a two-phase flow. Specifically, the lean
solvent heated in the regeneration reboiler 24 may at least partially change its phase to
saturated vapor and may be discharged to the reboiler outlet line 20b of the reboiler line
20 in a gas-liquid multiphase state. The lean solvent in a gas-liquid multiphase state is
10 returned to the regenerator 6 via the reboiler outlet line 20b, more specifically, it is
introduced to the bottom portion (below the chimney tray 46) of the regenerator 6 via the
reboiler outlet line 20b.
[0039] The saturated steam introduced to the bottom portion of the regenerator 6 via
the reboiler outlet line 20b raises in the regenerator 6 through the chimney tray 46, and is
15 used to heat the rich solvent in the release section 44 to release CO2 contained in the rich
solvent, as described above.
[0040] On the other hand, the lean solvent introduced to the bottom portion of the
regenerator 6 via the reboiler outlet line 20b (i.e., lean solvent that does not change phase
in the regeneration reboiler 24) is stored in the bottom portion of the regenerator 6. This
20 lean solvent is extracted from the bottom portion of the regenerator 6 via the lean solvent
line 16 and is supplied to the absorbing section 32 of the absorber 2 by the lean solvent
pump 17 disposed in the lean solvent line 16. The lean solvent thus returned to the
absorber 2 is reused as the absorption solvent for absorbing CO2 contained in the flue gas
in the absorbing section 32. The lean solvent flowing in the lean solvent line 16 is
25 cooled at the heat exchanger 18 by heat exchange with the rich solvent flowing in the
main rich solvent line 10.
[0041] The absorption solvent regeneration device 4 further includes a branch rich
13
solvent line 12 branching from the main rich solvent line 10 and a heating part 26 disposed
on the branch rich solvent line 12.
[0042] The branch rich solvent line 12 is connected to the reboiler outlet line 20b
which is a portion of the reboiler line 20 downstream of the regeneration reboiler 24. In
the exemplary embodiment shown in 5 FIG. 1, the branch rich solvent line 12 is provided
with a valve 14. The valve 14 can regulate the flow rate of the absorption solvent in the
branch rich solvent line 12 (the flow rate of the rich solvent branching from the main rich
solvent line 10 to the branch rich solvent line 12).
[0043] The branch rich solvent line 12 may be provided with a flow rate meter 50 for
10 measuring the flow rate of the absorption solvent in the branch rich solvent line 12.
Further, the opening degree of the valve 14 may be controlled based on the measurement
result of the flow rate meter 50, and the flow rate of the absorption solvent in the branch
rich solvent line 12 may be regulated according to the opening degree control.
[0044] The heating part 26 is configured to heat the absorption solvent (lean solvent)
15 flowing through the branch rich solvent line 12. In the exemplary embodiment shown
in FIG. 1, the heating part 26 is a heat exchanger configured to heat the absorption solvent
(lean solvent) flowing through the branch rich solvent line 12 by heat exchange with
condensed water of steam after heating the absorption solvent in the regeneration reboiler
24.
20 [0045] As described above, in the above-described absorption solvent regeneration
device 4, the absorption solvent (rich solvent) branching from the main rich solvent line
10 is first heated by the heating part 26 disposed on the branch rich solvent line 12, and
is then supplied to a portion (reboiler outlet line 20b) of the reboiler line 20 downstream
of the reboiler. As a result, compared to the case where the absorption solvent (rich) in
25 the main rich solvent line 10 is supplied to the regenerator 6 without branching, the
amount of heat required to heat the absorption solvent in the regeneration reboiler 24 can
be reduced, i.e., the amount of steam consumed in the regeneration reboiler 24 can be
14
reduced.
[0046] In the reboiler outlet line 20b, depending on the flow state of the fluid
including the absorption solvent (lean solvent), vibration may occur in a pipe that
constitutes the reboiler outlet line 20b. For example, when the flow from the
regeneration reboiler 24 is a two-phase flow 5 of gas-liquid mixture, this flow may become
a bulk flow (slug flow) or a ring flow (annular flow) depending on the ratio of gas and
liquid components, flow rate, and other factors. When the flow in the pipe is a bulk flow,
the pipe is likely to vibrate. In contrast, when the flow in the pipe is an annular flow,
the pipe is less likely to vibrate.
10 [0047] In this regard, in the above-described absorption solvent regeneration device
4, the absorption solvent (rich solvent) branching from the main rich solvent line 10 is
supplied to the reboiler outlet line 20b. As a result, even when the absorption solvent
regeneration device is in the operating condition where the flow in the reboiler outlet line
20b is generally a bulk flow, since the absorption solvent is supplied to the reboiler outlet
15 line 20b from the branch rich solvent line 12, the flow rate in the reboiler outlet line 20b
can be increased. Therefore, the flow in the reboiler outlet line 20b is more likely to be
an annular flow, so that vibration of the pipe can be suppressed by adjusting the flow state
in the reboiler outlet line 20b.
[0048] Further, in the above-described absorption solvent regeneration device 4,
20 since the branch rich solvent line 12 is connected to the reboiler line 20, for example,
compared to the case where the branch rich solvent line 12 is connected to the absorber 2
to reduce the consumption amount of the heating medium (e.g., steam) in the regeneration
reboiler 24, the cost of modifying the existing absorption solvent regeneration device 4
can be reduced, or the construction period can be shortened.
25 [0049] Further, when the valve 14 is disposed in the branch rich solvent line 12, the
flow rate of the absorption solvent in the branch rich solvent line 12 can be regulated by
the valve 14. As a result, the flux in the reboiler outlet line 20b connected with the
15
branch rich solvent line 12 can be easily regulated, and the flow state in the reboiler outlet
line 20b can be easily regulated.
[0050] Further, by regulating the opening degree of the valve 14 based on the
measurement result of the flow rate meter 50 disposed in the branch rich solvent line 12,
the flow rate of the absorption sol 5 vent in the branch rich solvent line 12 can be regulated
more appropriately. As a result, the flux in the reboiler outlet line 20b connected with
the branch rich solvent line 12 can be easily regulated, and the flow state in the reboiler
outlet line 20b can be easily regulated.
[0051] Further, in the above-described embodiment, the heating part 26 heats the
10 absorption solvent of the branch rich solvent line 12 by heat exchange with condensed
water of steam after heating the absorption solvent in the regeneration reboiler 24. In
other words, since the absorption solvent in the branch rich solvent line 12 is heated by
using excess heat of steam used in heating the absorption solvent in the regeneration
reboiler 24, compared to the case where the absorption solvent in the main rich solvent
15 line 10 is not branched (i.e., when the branch rich solvent line 12 is not provided), the
steam consumption amount in the regeneration reboiler 24 can be reduced, and the
operating efficiency of the absorption solvent regeneration device 4 can be improved as
a whole.
[0052] As shown in FIG. 1, the branch rich solvent line 12 may be branched from a
20 portion of the main rich solvent line 10 downstream of the heat exchanger 18. In this
case, since the rich solvent heated in the heat exchanger 18 flows through the branch rich
solvent line 12, it is possible to reduce the amount of heat exchange in the heating part
26.
[0053] FIGs. 2 and 3 are each a schematic diagram showing a connection portion
25 between the branch rich solvent line 12 and the reboiler outlet line 20b (reboiler line 20)
in the absorption solvent regeneration device 4 according to an embodiment.
[0054] As shown in FIGs. 2 and 3, the branch rich solvent line 12 has a connection
16
portion 52 with the reboiler outlet line 20b. The rich solvent 104 from the branch rich
solvent line 12 enters the reboiler outlet line 20b through the connection portion 52 and
joins the lean solvent 102 from the regeneration reboiler 24 in the reboiler outlet line 20b.
The mixed flow of the rich solvent 104 and the lean solvent 102 formed by this confluence
is returned to the 5 regenerator 6 via the reboiler outlet line 20b.
[0055] In the exemplary embodiment shown in FIG. 2, at the connection portion 52,
one end of the pipe constituting the branch rich solvent line 12 is connected to the wall
surface of the pipe constituting the reboiler outlet line 20b.
[0056] In the exemplary embodiment shown in FIG. 3, the connection portion 52 of
10 the branch rich solvent line 12 has a penetrating portion 52a penetrating the pipe
constituting the reboiler outlet line 20b, and a turning portion 52b connected to the
penetrating portion 52a. The center axis of the turning portion 52b is oblique to the
center axis of the penetrating portion 52a (the inclination angle is about 90 degrees in FIG.
2), Further, the turning portion 52b is disposed to extend along the center axis of the
15 reboiler outlet line 20b. With this configuration, the rich solvent 104 of the branch rich
solvent line 12 is turned at the connection portion 52 and smoothly joins the lean solvent
102 flowing through the reboiler outlet line 20b.
[0057] The above-described absorption solvent regeneration device 4 may be newly
constructed or formed by modification work to an existing absorption solvent
20 regeneration device. Hereinafter, the method for modifying the absorption solvent
regeneration device according to some embodiments will be described.
[0058] In the case of obtaining the absorption solvent regeneration device 4 by
modification work to the existing device, the absorption solvent regeneration device 4
may be obtained by modification work including additional installation of the branch rich
25 solvent line 12 and the heating part 26 to the existing device.
[0059] In some embodiments, the object of the modification work is an absorption
solvent regeneration device (existing device) that includes the regenerator 6 for
17
regenerating the absorption solvent, the main rich solvent line 10 for supplying the
absorption solvent to the regenerator 6, the regeneration reboiler 24, and the reboiler line
20 (see FIG. 1). In this case, the absorption solvent regeneration device 4 according to
an embodiment can be obtained by connecting one end of the pipe constituting the branch
rich solvent line 12 to the main rich solvent line 5 10 and connecting the other end of the
pipe to the reboiler outlet line 20b to additionally install the branch rich solvent line 12,
and installing the heating part 26 on the branch rich solvent line 12,
[0060] Further, in some embodiments, the valve 14 may be installed in the branch
rich solvent line 12.
10 [0061] With the above-described modifying method, by connecting the branch rich
solvent line 12 to the reboiler outlet line 20b (reboiler line 20), the absorption solvent
regeneration device 4 can be obtained. Therefore, unlike the case where the branch rich
solvent line is connected to the regenerator 6 in order to reduce the consumption amount
of the heating medium (e.g., steam) in the regeneration reboiler, no construction of the
15 regenerator 6 is required. Thus, the cost of modifying the existing absorption solvent
regeneration device can be reduced, or the construction period can be shortened.
[0062] Embodiments of the present invention were described in detail above, but the
present invention is not limited thereto, and various amendments and modifications may
be implemented.
20 [0063] Further, in the present specification, an expression of relative or absolute
arrangement such as “in a direction”, “along a direction”, “parallel”, “orthogonal”,
“centered”, “concentric” and “coaxial” shall not be construed as indicating only the
arrangement in a strict literal sense, but also includes a state where the arrangement is
relatively displaced by a tolerance, or by an angle or a distance whereby it is possible to
25 achieve the same function.
For instance, an expression of an equal state such as “same” “equal” and “uniform”
shall not be construed as indicating only the state in which the feature is strictly equal,
18
but also includes a state in which there is a tolerance or a difference that can still achieve
the same function.
Further, for instance, an expression of a shape such as a rectangular shape or a
cylindrical shape shall not be construed as only the geometrically strict shape, but also
includes a shape with unevenness or chamfered 5 corners within the range in which the
same effect can be achieved.
On the other hand, an expression such as “comprise”, “include”, “have”, “contain”
and “constitute” are not intended to be exclusive of other components.
10
19
Reference Signs List
[0064]
1 CO2 recovery device
2 Absorber
5 4 Absorption solvent regeneration device
6 Regenerator
8 Flue gas introduction line
10 Main rich solvent line
11 Rich solvent pump
10 12 Branch rich solvent line
14 Valve
16 Lean solvent line
17 Lean solvent pump
18 Heat exchanger
15 20 Reboiler line
20a Reboiler inlet line
20b Reboiler outlet line
22 Steam supply line
24 Regeneration reboiler (Reboiler)
20 26 Heating part
28 Recovery line
30 Condenser
32 Absorbing section
34 Washing section
25 36 Chimney tray
38 Circulation line
39 Circulation pump
20
40 Demister
42 Tower top portion
44 Release section
46 Chimney tray
5 48 Demister
50 Flow rate meter
52 Connection portion
52a Penetrating portion
52b Turning portion
10 54 Chimney tray
102 Lean solvent
104 Rich solvent

We Claim:

1. An absorption solvent regeneration device, comprising:
a regenerator for regenerating an absorption solvent by separating CO2 from
5 the absorption solvent which has absorbed CO2;
a main rich solvent line for supplying the absorption solvent which has
absorbed CO2 to the regenerator;
a regeneration reboiler for heating an absorption solvent extracted from the
regenerator;
10 a reboiler line configured to extract the absorption solvent stored in the
regenerator and return the absorption solvent to the regenerator via the regeneration
reboiler;
a branch rich solvent line branching from the main rich solvent line and
connected to a portion of the reboiler line downstream of the regeneration reboiler;
15 and
a heating part for heating the absorption solvent flowing through the branch
rich solvent line, the heating part being disposed on the branch rich solvent line.
2. The absorption solvent regeneration device according to claim 1,
wherein the regeneration reboiler is configured such that a flow of the
20 absorption solvent discharged from the regeneration reboiler to the reboiler line is
a two-phase flow.
3. The absorption solvent regeneration device according to claim 1 or 2, further
comprising a steam supply line for supplying steam for heating the absorption
solvent to the regeneration reboiler,
25 wherein the heating part includes a heat exchanger configured to exchange
heat between condensed water of steam after heating the absorption solvent in the
regeneration reboiler and the absorption solvent flowing through the branch rich
22
solvent line.
4. The absorption solvent regeneration device according to any one of claims 1 to 3,
further comprising a valve for regulating a flow rate of the absorption solvent in the
branch rich solvent line, the valve being disposed in the branch rich solvent line.
5 5. A CO2 recovery device, comprising:
an absorber configured to cause CO2 in a flue gas to be absorbed by an
absorption solvent by bringing the flue gas containing CO2 and the absorption
solvent into contact; and
the absorption solvent regeneration device according to any one of claims 1
10 to 4,
wherein the main rich solvent line is configured to supply the absorption
solvent which has absorbed CO2 in the absorber to the regenerator.
6. A method for modifying an absorption solvent regeneration device, the absorption
solvent regeneration device including:
15 a regenerator for regenerating an absorption solvent by separating CO2 from
the absorption solvent which has absorbed CO2;
a main rich solvent line for supplying the absorption solvent which has
absorbed CO2 to the regenerator;
a regeneration reboiler for heating an absorption solvent extracted from the
20 regenerator; and
a reboiler line configured to extract the absorption solvent stored in the
regenerator and return the absorption solvent to the regenerator via the regeneration
reboiler;
the method comprising a step of additionally installing a branch rich solvent
25 line branching from the main rich solvent line and connected to a portion of the
reboiler line downstream of the regeneration reboiler, and a heating part for heating
the absorption solvent flowing through the branch rich solvent line, the heating part
23
being disposed in the branch rich solvent line.
7. The method for modifying an absorption solvent regeneration device according to
claim 6, further comprising a step of installing, in the branch rich solvent line, a
valve for regulating a flow rate of the absorption solvent in the branch rich solvent
5 line.