[0001] The present disclosure relates to an absorption solvent regeneration device, a
CO2 recovery device, and an absorption solvent regeneration method.
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.
25 Citation List
Patent Literature
[0005] Patent Document 1: JP2005-254212A
3
SUMMARY
Problems to be Solved
[0006] In the absorption solvent regeneration device including the absorber, a fluid
derived from the absorption solvent and a fluid after heat exchange with the absorption
solvent are sometimes extracted as a product and used 5 in a facility. Such a fluid (e.g.,
product CO2 or steam condensed water) obtained from the device is required to satisfy a
predetermined temperature condition according to the application.
[0007] On the other hand, for example as in the device described in Patent Document
1, in the case of a device in which part of the absorption solvent (rich solvent) from the
10 absorber to the regenerator is branched and led to the regenerator, the temperature at the
top portion of the absorber tends to rise. Accordingly, the temperature of the fluid
(product CO2) taken out of the device via the top portion of the absorber tends to increase,
and may exceed the temperature condition required for the product. In addition, since
the temperature of the fluid obtained from the device can fluctuate due to changes in the
15 operating condition (temperature, etc.) of the device, for example, when the temperature
is high or low, it may not be possible to maintain the temperature of the fluid within an
appropriate range. Otherwise, when the temperature condition required for the fluid
obtained from the device is changed, the temperature of the fluid needs to be changed
appropriately.
20 For these reasons, it is desirable to appropriately regulate the temperature of the
fluid obtained from the device.
[0008] 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 an absorption solvent regeneration method whereby it is possible to easily control the
25 temperature of a fluid obtained from the absorption solvent regeneration device.
Solution to the Problems
[0009] (1) An absorption solvent regeneration device according to at least one
4
embodiment of the present invention comprises:
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 first heating part for
heating the absorption solvent flowing 5 through the main rich solvent line, the first heating
part being disposed on the main rich solvent line; and a branch rich solvent line for
supplying a part of the absorption solvent flowing through the main rich solvent line to
the regenerator, the branch rich solvent line branching from the main rich solvent line.
The branch rich solvent line includes: a first branch portion branching from a first branch
10 point disposed on the main rich solvent line and upstream of the first heating part; and a
second branch portion branching from a second branch point disposed on the main rich
solvent line and downstream of the first heating part. The absorption solvent
regeneration device further comprises a regulating part for regulating a ratio between a
first flow rate of the absorption solvent flowing through the first branch portion and a
15 second flow rate of the absorption solvent flowing through the second branch portion.
[0010] With the above configuration (1), since the ratio between the first flow rate of
the absorption solvent with a relatively low temperature flowing through the first branch
portion and the second flow rate of the absorption solvent with a relatively high
temperature flowing through the second branch portion can be regulated, the temperature
20 of the absorption solvent downstream of the junction point between the first branch
portion and the second branch portion or the temperature of the absorption solvent in the
main rich solvent line and downstream of the first heating part can be regulated.
Accordingly, the temperature of a fluid derived from the absorption solvent of the
absorption solvent regeneration device or a fluid which exchanges heat with the
25 absorption solvent in the absorption solvent regeneration device can be regulated. Thus,
it is possible to regulate the temperature of the fluid obtained from the absorption solvent
regeneration device within a desired range.
5
[0011] (2) In some embodiments, in the above configuration (1), the regulating part
is configured to regulate a flow rate of the absorption solvent distributed from the main
rich solvent line to the branch rich solvent line.
[0012] With the above configuration (2), in addition to that the ratio between the first
flow rate and the second flow rate can be regulated 5 as described above, the flow rate of
the absorption solvent distributed from the main rich solvent line to the branch rich
solvent line can be regulated, so the amount of heat exchange between the absorption
solvent and a heating medium in the heat exchanger, etc., can be regulated more flexibly.
Thus, it is possible to more flexibly regulate the temperature of the fluid obtained from
10 the absorption solvent regeneration device.
[0013] (3) In some embodiments, in the above configuration (1) or (2), the regulating
part includes at least one of a first valve, disposed on the first branch portion, for
regulating the first flow rate or a second valve, disposed on the second branch portion,
for regulating the second flow rate.
15 [0014] With the above configuration (3), since at least one of the first valve for
regulating the first flow rate or the second valve for regulating the second flow rate is
disposed, the ratio between the first flow rate and the second flow rate and the flow rate
of the absorption solvent distributed from the main rich solvent line to the branch rich
solvent line can be easily regulated.
20 For example, by regulating the flow rate in the first branch portion by the regulation
of the first valve, the temperature of the absorption solvent having passed through the first
heater (the absorption solvent in the second branch portion and downstream of the first
heater of the main rich solvent line) can be appropriately regulated. Further, by
regulating the first valve and/or the second valve, the flow rate of the absorption solvent
25 flowing through respective portions of the main rich solvent line and the branch rich
solvent line can be appropriately regulated.
[0015] (4) In some embodiments, in any one of the above configurations (1) to (3),
6
the regulating part is configured to regulate the ratio between the first flow rate and the
second flow rate such that a temperature of a tower top portion of the regenerator is within
a specified range.
[0016] CO2 gas released from the absorption solvent heated in the regenerator is
recovered through the tower top portion of the regenerator 5 as a product CO2. In this
regard, with the above configuration (4), since the ratio between the first flow rate and
the second flow rate is regulated such that the temperature of the tower top portion of the
regenerator is within a specified range, the temperature of the product CO2 recovered
from the absorption solvent regeneration device can be easily regulated within an
10 appropriate range by setting this ratio appropriately.
[0017] (5) In some embodiments, in any one of the above configurations (1) to (4),
the regulating part is configured to regulate the ratio between the first flow rate and the
second flow rate such that a temperature of the absorption solvent in the main rich solvent
line and downstream of the second branch portion is within a specified range.
15 [0018] The temperature of the absorption solvent in the main rich solvent line and
downstream of the second branch portion may serve as an index of the temperature at the
tower top portion of the regenerator, and the higher the temperature of the absorption
solvent in the main rich solvent line, the higher the temperature at the tower top portion
of the regenerator tends to be. In this regard, with the above configuration (5), since the
20 ratio between the first flow rate and the second flow rate is regulated such that the
temperature of the absorption solvent in the main rich solvent line and downstream of the
second branch portion is within a specified range, the temperature of the product CO2
recovered from the absorption solvent regeneration device can be easily regulated within
an appropriate range by setting this ratio appropriately.
25 [0019] (6) In some embodiments, in any one of the above configurations (1) to (5),
the branch rich solvent line includes a downstream portion which is a portion downstream
of a junction point between the first branch portion and the second branch portion. The
7
absorption solvent regeneration device further comprises: a regeneration reboiler for
heating the absorption solvent extracted from the regenerator by heat exchange with
steam; a steam line through which steam to be supplied to the regeneration reboiler flows;
and a second heating part disposed on the steam line and configured to heat the absorption
solvent flowing through the downstream portion by heat 5 exchange with condensed water
of steam after heating the absorption solvent in the regeneration reboiler. The regulating
part is configured to regulate the ratio between the first flow rate and the second flow rate
such that a temperature of the condensed water in the steam line and downstream of the
second heating part is within a specified range.
10 [0020] Condensed water of steam after heating the absorption solvent in the
regeneration reboiler may be used inside or outside the absorption solvent regeneration
device. In this regard, with the above configuration (6), since the ratio between the first
flow rate and the second flow rate is regulated such that the temperature of the condensed
water in the steam line and downstream of the second heating part is within a specified
15 range, the temperature of the steam condensed water obtained from the absorption solvent
regeneration device can be easily regulated within an appropriate range by setting this
ratio appropriately.
[0021] (7) In some embodiments, in any one of the above configurations (1) to (6),
the branch rich solvent line includes a downstream portion which is a portion downstream
20 of a junction point between the first branch portion and the second branch portion. The
absorption solvent regeneration device further comprises: a regeneration reboiler for
heating the absorption solvent extracted from the regenerator by heat exchange with
steam; a steam line through which steam to be supplied to the regeneration reboiler flows;
and a second heating part disposed on the steam line and configured to heat the absorption
25 solvent flowing through the downstream portion by heat exchange with condensed water
of steam after heating the absorption solvent in the regeneration reboiler. The regulating
part is configured to regulate the ratio between the first flow rate and the second flow rate
8
such that a temperature of the absorption solvent which is an upstream side more than the
second heating part in the downstream portion is within a specified range.
[0022] The temperature of the absorption solvent which is an upstream side more
than the second heating part in the downstream portion of the branch rich solvent line
may serve as an index of the temperature of condensed 5 water in the steam line and
downstream of the second heating part, and the higher the temperature of the absorption
solvent, the higher the temperature of condensed water in the steam line tends to be. In
this regard, with the above configuration (7), since the ratio between the first flow rate
and the second flow rate is regulated such that the temperature of the absorption solvent
10 which is an upstream side more than the second heating part in the downstream portion
of the branch rich solvent line is within a specified range, the temperature of the steam
condensed water obtained from the absorption solvent regeneration device can be easily
regulated within an appropriate range by setting this ratio appropriately.
[0023] (8) A CO2 recovery device according to at least one embodiment of the present
15 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
above (1) to (7). The main rich solvent line is configured to supply the absorption
solvent which has absorbed CO2 in the absorber to the regenerator.
20 [0024] With the above configuration (8), since the ratio between the first flow rate of
the absorption solvent with a relatively low temperature flowing through the first branch
portion and the second flow rate of the absorption solvent with a relatively high
temperature flowing through the second branch portion can be regulated, the temperature
of the absorption solvent downstream of the junction point between the first branch
25 portion and the second branch portion or the temperature of the absorption solvent in the
main rich solvent line and downstream of the first heating part can be regulated.
Accordingly, the temperature of a fluid derived from the absorption solvent in the
9
absorption solvent regeneration device or a fluid which exchanges heat with the
absorption solvent in the absorption solvent regeneration device can be regulated. Thus,
it is possible to regulate the temperature of the fluid obtained from the absorption solvent
regeneration device within a desired range.
[0025] (9) An absorption solvent 5 regeneration method according to at least one
embodiment of the present invention comprises: a step of supplying an absorption solvent
which has absorbed CO2 to a regenerator via a main rich solvent line; a step of
regenerating the absorption solvent by separating CO2 from the absorption solvent in the
regenerator; a step of heating the absorption solvent flowing through the main rich solvent
10 line by a first heating part disposed on the main rich solvent line; and a step of distributing
a part of the absorption solvent flowing through the main rich solvent line to a branch rich
solvent line branching from the main rich solvent line. The step of distributing includes
distributing a part of the absorption solvent to a first branch portion branching from a first
branch point disposed on the main rich solvent line and upstream of the first heating part
15 and a second branch portion branching from a second branch point disposed on the main
rich solvent line and downstream of the first heating part. The absorption solvent
regeneration method further comprising a regulating step of regulating a ratio between a
first flow rate of the absorption solvent flowing through the first branch portion and a
second flow rate of the absorption solvent flowing through the second branch portion.
20 [0026] With the above method (9), since the ratio between the first flow rate of the
absorption solvent with a relatively low temperature flowing through the first branch
portion and the second flow rate of the absorption solvent with a relatively high
temperature flowing through the second branch portion can be regulated, the temperature
of the absorption solvent downstream of the junction point between the first branch
25 portion and the second branch portion or the temperature of the absorption solvent in the
main rich solvent line and downstream of the first heating part can be regulated.
Accordingly, the temperature of a fluid derived from the absorption solvent of the
10
absorption solvent regeneration device or a fluid which exchanges heat with the
absorption solvent in the absorption solvent regeneration device can be regulated. Thus,
it is possible to regulate the temperature of the fluid obtained from the absorption solvent
regeneration device within a desired range.
[0027] (10) 5 In some embodiments, in the above method (9), the regulating step
includes regulating a flow rate of the absorption solvent distributed from the main rich
solvent line to the branch rich solvent line.
[0028] With the above method (10), the flow rate of the absorption solvent distributed
from the main rich solvent line to the branch rich solvent line can be regulated, so the
10 amount of heat exchange between the absorption solvent and a fluid derived from the
absorption solvent or a fluid which exchanges heat with the absorption solvent can be
regulated more flexibly. Thus, it is possible to more flexibly regulate the temperature of
the fluid obtained from the absorption solvent regeneration device.
[0029] (11) In some embodiments, in the above method (9) or (10), the regulating
15 step includes regulating the first flow rate by a first valve disposed on the first branch
portion or regulating the second flow rate by a second valve disposed on the second
branch portion.
[0030] With the above method (11), since at least one of the first valve for regulating
the first flow rate or the second valve for regulating the second flow rate is disposed, the
20 ratio between the first flow rate and the second flow rate and the flow rate of the
absorption solvent distributed from the main rich solvent line to the branch rich solvent
line can be easily regulated.
For example, by regulating the flow rate in the first branch portion by the regulation
of the first valve, the temperature of the absorption solvent having passed through the first
25 heater (the absorption solvent in the second branch portion and downstream of the first
heater of the main rich solvent line) can be appropriately regulated. Further, by
regulating the first valve and/or the second valve, the flow rate of the absorption solvent
11
flowing through respective portions of the main rich solvent line and the branch rich
solvent line can be appropriately regulated.
[0031] (12) In some embodiments, in any one of the above methods (9) to (11), the
regulating step includes regulating the ratio between the first flow rate and the second
flow rate such that a temperature of a 5 tower top portion of the regenerator is within a
specified range.
[0032] CO2 gas released from the absorption solvent heated in the regenerator is
recovered through the tower top portion of the regenerator as a product CO2. In this
regard, with the above method (12), since the ratio between the first flow rate and the
10 second flow rate is regulated such that the temperature of the tower top portion of the
regenerator is within a specified range, the temperature of the product CO2 recovered
from the absorption solvent regeneration device can be easily regulated within an
appropriate range by setting this ratio appropriately.
[0033] (13) In some embodiments, in any one of the above methods (9) to (12), the
15 regulating step includes regulating the ratio between the first flow rate and the second
flow rate such that a temperature of the absorption solvent in the main rich solvent line
and downstream of the second branch portion is within a specified range.
[0034] The temperature of the absorption solvent in the main rich solvent line and
downstream of the second branch portion may serve as an index of the temperature at the
20 tower top portion of the regenerator, and the higher the temperature of the absorption
solvent in the main rich solvent line, the higher the temperature at the tower top portion
of the regenerator tends to be. In this regard, with the above method (13), since the ratio
between the first flow rate and the second flow rate is regulated such that the temperature
of the absorption solvent in the main rich solvent line and downstream of the second
25 branch portion is within a specified range, the temperature of the product CO2 recovered
from the absorption solvent regeneration device can be easily regulated within an
appropriate range by setting this ratio appropriately.
12
[0035] (14) In some embodiments, in any one of the above methods (9) to (13), the
branch rich solvent line includes a downstream portion which is a portion downstream of
a junction point between the first branch portion and the second branch portion. The
absorption solvent regeneration method further comprises: a step of extracting the
absorption solvent from the regenerator 5 and heating the absorption solvent by heat
exchange with steam in a regeneration reboiler; a step of supplying the steam to the
regeneration reboiler via a steam line; and a step of heating, in a second heating part
disposed on the steam line, the absorption solvent flowing through the downstream
portion by heat exchange with condensed water of steam after heating the absorption
10 solvent in the regeneration reboiler. The regulating step includes regulating the ratio
between the first flow rate and the second flow rate such that a temperature of the
condensed water in the steam line and downstream of the second heating part is within a
specified range.
[0036] Condensed water of steam after heating the absorption solvent in the
15 regeneration reboiler may be used inside or outside the absorption solvent regeneration
device. In this regard, with the above method (14), since the ratio between the first flow
rate and the second flow rate is regulated such that the temperature of the condensed water
in the steam line and downstream of the second heating part is within a specified range,
the temperature of the steam condensed water obtained from the absorption solvent
20 regeneration device can be easily regulated within an appropriate range by setting this
ratio appropriately.
[0037] (15) In some embodiments, in any one of the above methods (9) to (14), the
branch rich solvent line includes a downstream portion which is a portion downstream of
a junction point between the first branch portion and the second branch portion. The
25 absorption solvent regeneration method further comprises: a step of extracting the
absorption solvent from the regenerator and heating the absorption solvent by heat
exchange with steam in a regeneration reboiler; a step of supplying the steam to the
13
regeneration reboiler via a steam line; and a step of heating, in a second heating part
disposed on the steam line, the absorption solvent flowing through the downstream
portion by heat exchange with condensed water of steam after heating the absorption
solvent in the regeneration reboiler. The regulating step includes regulating the ratio
between the first flow rate and the 5 second flow rate such that a temperature of the
absorption solvent which is an upstream side more than the second heating part in the
downstream portion is within a specified range.
[0038] The temperature of the absorption solvent which is an upstream side more
than the second heating part in the downstream portion of the branch rich solvent line
10 may serve as an index of the temperature of condensed water in the steam line and
downstream of the second heating part, and the higher the temperature of the absorption
solvent, the higher the temperature of condensed water in the steam line tends to be. In
this regard, with the above method (15), since the ratio between the first flow rate and the
second flow rate is regulated such that the temperature of the absorption solvent which is
15 an upstream side more than the second heating part in the downstream portion of the
branch rich solvent line is within a specified range, the temperature of the steam
condensed water obtained from the absorption solvent regeneration device can be easily
regulated within an appropriate range by setting this ratio appropriately.
Advantageous Effects
20 [0039] At least one embodiment of the present invention provides an absorption
solvent regeneration device, a CO2 recovery device, and an absorption solvent
regeneration method whereby it is possible to easily control the temperature of a fluid
obtained from the absorption solvent regeneration device.
BRIEF DESCRIPTION OF DRAWINGS
25 [0040] FIG. 1 is a schematic diagram of a CO2 recovery device including an
absorption solvent regeneration device according to an embodiment.
14
FIG. 2 is a schematic diagram of a CO2 recovery device including an absorption
solvent regeneration device according to an embodiment.
DETAILED DESCRIPTION
[0041] Embodiments of the present invention will now be described in detail with
reference to the accompanying 5 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
intended to limit the scope of the present invention.
[0042] FIGs. 1 and 2 are each a schematic diagram of a CO2 recovery device
10 including an absorption solvent regeneration device according to an embodiment of the
present invention. The CO2 recovery apparatus shown in FIGs. 1 and 2 is a device for
recovering CO2 from exhaust gas discharged from a power generation facility, a plant, or
the like. As 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
15 absorption solvent regeneration device 4 including a regenerator 6 for regenerating the
absorption solvent 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, a regeneration reboiler (reboiler) 24 for heating the absorption
solvent stored in the regenerator 6, and a reboiler line 20 configured to introduce the
20 absorption solvent stored in the regenerator 6 to the regeneration reboiler 24.
[0043] Flue gas from a plant or the like is introduced 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.
[0044] The absorber 2 includes an absorbing section 32 for absorbing CO2 gas in the
25 flue gas, a washing section 34 for washing the flue gas from which the CO2 gas has been
removed, and a demister 40, disposed above the washing section 34, for removing mist
in the flue gas.
15
[0045] 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.
The flue gas entering the absorber 2 through the flue gas introduction line 8 flows upward
in the absorber 2 from the bottom 5 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
removed from the flue gas. The absorbing section 32 may be formed by a packed layer
10 packed with a packing material made of any material.
[0046] 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
other than amines such as sodium hydroxide, potassium hydroxide, and calcium
15 hydroxide can be used as the CO2 absorption agent.
[0047] The absorption solvent which has absorbed CO2 from the flue gas in the
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
20 (lean solvent) stored in the bottom portion of the regenerator 6, described later.
[0048] The washing section 34 is 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
25 washing section 34, the CO2 recovery agent contained in the flue gas is dissolved in the
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
16
34 and stored in the chimney tray 36 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.
[0049] The flue gas from which the CO2 absorption agent has been removed passes
through the demister 40 disposed above the washing 5 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.
[0050] 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
10 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 first heat exchanger 18 (first heating part) 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
15 later. By heating the rich solvent through heat exchange with the lean solvent of
relatively high temperature in the first heat exchanger 18, it is possible to promote the
regeneration of the absorption solvent in the regenerator 6 described below.
[0051] 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
20 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 embodiment shown in FIG. 1, the
release section 44 includes a first release section 44A and a second release section 44B
disposed below the first release section 44A.
In the release section 44, the rich solvent supplied as described above is heated by
25 saturated 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.
17
[0052] The CO2 gas released from the rich solvent in the release section 44 rises
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 5 30 is configured to cool the CO2 gas
discharged from the regenerator 6 by heat exchange with cooling water to condense
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
10 condensate.
[0053] The regenerator 6 is connected to a reboiler line 20 with a regeneration
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)
15 introduced through the reboiler line 20, by heat exchange with a heating medium. The
regeneration reboiler 24 is supplied with steam as the heating medium via a steam line
22.
[0054] 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
20 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 line 22.
[0055] The lean solvent heated in the regeneration reboiler 24 at least partially
changes its phase to saturated vapor and is discharged to the reboiler outlet line 20b of
25 the reboiler line 20 in a gas-liquid multiphase state. The absorption solvent (lean
solvent) discharged from the regeneration reboiler 24 is returned to the regenerator 6 via
the reboiler outlet line 20b, more specifically, it is introduced to the bottom portion (below
18
the chimney tray 46) of the regenerator 6 via the reboiler outlet line 20b.
[0056] 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
used to heat the rich solvent in the release section 44 to release CO2 contained in the rich
5 solvent, as described above.
[0057] 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
lean solvent is extracted from the bottom portion of the regenerator 6 via the lean solvent
10 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
cooled at the first heat exchanger 18 by heat exchange with the rich solvent flowing in
15 the main rich solvent line 10.
[0058] The absorption solvent regeneration device 4 further includes a branch rich
solvent line 12 branching from the main rich solvent line 10. The branch rich solvent
line 12 is configured to supply part of the absorption solvent (rich solvent) flowing
through the main rich solvent line 10 to the regenerator 6.
20 [0059] The branch rich solvent line 12 includes a first branch portion 12a branching
from a first branch point 61 disposed on the main rich solvent line 10 and upstream of the
first heat exchanger 18 (first heating part) and a second branch portion 12b branching
from a second branch point 62 disposed on the main rich solvent line 10 and downstream
of the first heat exchanger 18. Further, the branch rich solvent line 12 includes a
25 downstream portion 12c which is a portion downstream of a junction point between the
first branch portion 12a and the second branch portion 12b.
[0060] Since the first branch portion 12a is branched off from the main rich solvent
19
line 10 at a position upstream of the first heat exchanger 18, the absorption solvent that
has not been heated by the first heat exchanger 18 flows into the first branch portion 12a.
On the other hand, since the second branch portion 12b is branched off from the main rich
solvent line 10 at a position downstream of the first heat exchanger 18, the absorption
solvent that has been heated by the first heat exchanger 5 18 flows into the second branch
portion 12b. Therefore, the temperature of the absorption solvent flowing through the
second branch portion 12b is higher than the temperature of the absorption solvent
flowing through the first branch portion.
[0061] In the exemplary embodiment shown in FIG. 1, the downstream portion 12c
10 of the branch rich solvent line 12 is connected to the regenerator 6, and the absorption
solvent (rich solvent) from the downstream portion 12c is supplied to an upper portion of
the second release section 44B. The absorption solvent thus supplied to the second
release section 44B is heated with saturated steam from the regeneration reboiler 24 as
with the absorption solvent supplied from the main rich solvent line 10 to the release
15 sections 44A, 44B.
[0062] In the exemplary embodiment shown in FIG. 2, the downstream portion 12c
of the branch rich solvent line 12 is connected to the reboiler outlet line 20b. The
absorption solvent (rich solvent) entering the reboiler outlet line 20b via the downstream
portion 12c joins the absorption solvent (lean solvent) discharged from the regeneration
20 reboiler 24 to the reboiler outlet line 20b and flows into the tower bottom portion of the
regenerator 6.
[0063] In the absorption solvent regeneration device 4 shown in FIGs. 1 and 2, a
second heat exchanger 26 (second heating part) is disposed on the steam line 22 through
which steam supplied to the regeneration reboiler 24 flows. The second heat exchanger
25 26 is configured to exchange heat between the absorption solvent flowing through the
downstream portion 12c of the branch rich solvent line 12 and condensed water of steam
after heating the absorption solvent in the regeneration reboiler 24. Thus, the absorption
20
solvent flowing through the downstream portion 12c is heated.
[0064] The steam condensed water introduced to the second heat exchanger 26 via
the steam line 22 is cooled by heat exchange with the absorption solvent and then is
discharged from the second heat exchanger 26. The steam condensed water thus
discharged from the second heat exchanger 26 is 5 supplied to and used in a facility such
as a boiler.
[0065] The absorption solvent regeneration device 4 further includes a regulating part
60 for regulating a ratio between the first flow rate of the absorption solvent (rich solvent)
flowing through the first branch portion 12a and the second flow rate of the absorption
10 solvent (rich solvent) flowing through the second branch portion 12b.
[0066] In the exemplary embodiments shown in FIGs. 1 and 2, the regulating part 60
includes a first valve 14 disposed in the first branch portion 12a and a second valve 15
disposed in the second branch portion 12b. The first valve 14 is configured to regulate
the first flow rate of the absorption solvent flowing through the first branch portion 12a.
15 The second valve 15 is configured to regulate the second flow rate of the absorption
solvent flowing through the second branch portion 12b.
In some embodiments, in the absorption solvent regeneration device 4, only one of
the first valve 14 or the second valve 15 may be disposed.
[0067] The first branch portion 12a may be provided with a flow rate sensor 50 for
20 measuring the flow rate of the absorption solvent in the first branch portion 12a. The
second branch portion 12b may be provided with a flow rate sensor 51 for measuring the
flow rate of the absorption solvent in the second branch portion 12b.
[0068] The regulating part 60 may include a controller (not shown) configured to
control the opening degree of the first valve 14 and/or the second valve 15. Alternatively,
25 the opening degree of the first valve 14 and/or the second valve 15 may be controlled by
manual operation.
[0069] The controller may be configured to control the opening degree of the first
21
valve 14 and/or the second valve 15 based on a measurement result of the flow rate sensor
50, 51. Further, the controller may be configured to control the opening degree of the
first valve 14 and/or the second valve 15 based on a measurement result of temperature
sensors 71 to 75 disposed at predetermined positions of the absorption solvent
5 regeneration device 4.
[0070] As already described, in the absorption solvent regeneration device 4, a fluid
derived from the absorption solvent and a fluid after heat exchange with the absorption
solvent can be recovered as a product and used in a facility. For example, as described
above, CO2 gas (fluid derived from the absorption solvent) released from the absorption
10 solvent in the regenerator 6 is recovered as a product CO2 via the recovery line 28
connected to the tower top portion of the regenerator 6. Meanwhile, condensed water
of steam having passed through the regeneration reboiler 24 in the steam line 22 (fluid
after heat exchange with the absorption solvent) is used in a facility such as a boiler after
heat exchange in the second heat exchanger 26 with the absorption solvent flowing
15 through the downstream portion 12c. Such product CO2 and steam condensed water
obtained from the absorption solvent regeneration device 4 are required to satisfy a
predetermined temperature condition according to the application.
[0071] On the other hand, as in the absorption solvent regeneration device 4 shown
in FIG. 1 or FIG. 2, in the case of a device in which part of the absorption solvent (rich
20 solvent) from the absorber 2 to the regenerator 6 is branched and led to the regenerator 6,
the temperature at the top portion of the absorber may rise.
For example, in the absorption solvent regeneration device 4 shown in FIG. 1 or 2,
the higher the branch flow rate from the position upstream of the first heat exchanger 18
in the main rich solvent line 10 (the first flow rate of the absorption solvent in the first
25 branch portion 12a), the less absorption solvent (rich solvent) is supplied to the first heat
exchanger 18. Accordingly, the temperature downstream of the first heat exchanger 18
in the main rich solvent line 10 rises, and the rich solvent with the raised temperature is
22
supplied to the regenerator 6 via the main rich solvent line 10. Here, since the
temperature at the tower top portion of the regenerator 6 depends on the temperature of
the rich solvent supplied via the main rich solvent line 10, the temperature at the tower
top portion of the regenerator 6 increases. Accordingly, the temperature of product CO2
recovered via the tower top portion of the regenerator 5 6 and the recovery line 28 also
increases, and may exceed the temperature condition required for the product.
[0072] In addition, since the temperature of the fluid obtained from the device can
fluctuate due to changes in the operating condition (temperature, etc.) of the device, it
may not be possible to maintain the temperature of the fluid within an appropriate range.
10 For example, the temperature of cooling water supplied to the condenser 30
disposed on the recovery line 28 fluctuates with the seasons. The temperature of cooling
water is higher in summer at high temperature and is lower in winter at low temperature.
Further, since the temperature of CO2 gas cooled in the condenser 30 is affected by the
cooling water temperature, if the cooling water temperature is too high or too low, the
15 temperature of CO2 recovered after passing through the condenser 30 may deviate from
the temperature condition.
[0073] Otherwise, the temperature of steam condensed water from the second heat
exchanger 26 may need to be changed when there is a change in the configuration of the
facility (e.g., boiler) to which the steam condensed water is supplied.
20 [0074] In this regard, with the absorption solvent regeneration device 4 according to
the above-described embodiments, the ratio between the first flow rate of the absorption
solvent with a relatively low temperature flowing through the first branch portion 12a and
the second flow rate of the absorption solvent with a relatively high temperature flowing
through the second branch portion 12b can be regulated by the regulating part 60. As a
25 result, the temperature T1 (temperature at the position of the first temperature sensor 71)
of the absorption solvent in the downstream portion 12c downstream of the junction point
between the first branch portion 12a and the second branch portion 12b, or the
23
temperature T2 (temperature at the position of the second temperature sensor 72) of the
absorption solvent downstream of the first heat exchanger 18 in the main rich solvent line
10 can be regulated. Accordingly, the temperature of a fluid (e.g., product CO2) derived
from the absorption solvent of the absorption solvent regeneration device 4 or a fluid (e.g.,
steam condensed water) which 5 exchanges heat with the absorption solvent in the
absorption solvent regeneration device 4 can be regulated.
[0075] The ratio F1/F2 may be regulated by regulating the opening degree of at least
one of the first valve 14 or the second valve 15.
[0076] For example, when lowering the temperature T2 of the absorption solvent
10 downstream of the first heat exchanger 18 in the main rich solvent line 10, the regulating
part 60 (e.g., the first valve 14 and/or the second valve 15) may be controlled so as to
reduce the ratio F1/F2 between the first flow rate F1 of the absorption solvent with
relatively low temperature in the first branch portion 12a and the second flow rate F2 of
the absorption solvent with relatively high temperature in the second branch portion 12b.
15 Meanwhile, for example, when rising the temperature T1 of the absorption solvent
in the downstream portion 12c of the branch rich solvent line 12, the regulating part 60
(e.g., the first valve 14 and/or the second valve 15) may be controlled so as to reduce the
ratio F1/F2 between the first flow rate F1 of the absorption solvent with relatively low
temperature in the first branch portion 12a and the second flow rate F2 of the absorption
20 solvent with relatively high temperature in the second branch portion 12b.
[0077] Thus, by regulating the ratio F1/F2 between the first flow rate F1 of the
absorption solvent with a relatively low temperature flowing through the first branch
portion 12a and the second flow rate F2 of the absorption solvent with a relatively high
temperature flowing through the second branch portion 12b by the regulating part 60, the
25 temperature of the fluid obtained from the absorption solvent regeneration device 4 can
be easily regulated in a desired range.
[0078] The regulating part 60 may be configured to regulate the ratio F1/F2 between
24
the first flow rate F1 and the second flow rate F2 as described above, and further regulate
the branch flow rate (F1+F2), which is the flow rate of the absorption solvent distributed
from the main rich solvent line 10 to the branch rich solvent line 12 (first branch portion
12a and second branch portion 12b).
The ratio F1/F2 and 5 the branch flow rate (F1+F2) may be regulated by regulating
the opening degree of at least one of the first valve 14 or the second valve 15.
[0079] In this case, since the flow rate of the absorption solvent distributed from the
main rich solvent line 10 to the branch rich solvent line 12 can also be regulated, for
example, the amount of heat exchange between the absorption solvent flowing through
10 the downstream portion 12c of the branch rich solvent line 12 and the condensed water
in the second heat exchanger 26 can be regulated more flexibly. Thus, it is possible to
more flexibly regulate the temperature of the fluid (e.g., steam condensed water) obtained
from the absorption solvent regeneration device 4.
[0080] In some embodiments, the regulating part 60 may be configured to regulate
15 the ratio F1/F2 between the first flow rate F1 and the second flow rate F2 such that the
temperature T3 of the tower top portion of the regenerator 6 is within a specified range.
Alternatively, the regulating part 60 may be configured to regulate, as well as the ratio
F1/F2, the first flow rate F1 and the second flow rate F2 such that the temperature T3 of
the tower top portion of the regenerator 6 is within a specified range. The temperature
20 of a portion of the recovery line 28, which communicates with the tower top portion,
upstream of the condenser 30 (i.e., the temperature at the third temperature sensor 73)
may be regarded as the temperature T3 of the tower top portion of the regenerator 6.
[0081] The regulating part 60 may regulate the ratio F1/F2, the first flow rate F1, and
the second flow rate F2 by regulating the opening degree of the first valve 14 and the
25 second valve 15 based on a detected temperature by the third temperature sensor 73
disposed in the recovery line 28 and upstream of the condenser 30.
[0082] CO2 gas released from the absorption solvent heated in the regenerator 6 is
25
recovered through the tower top portion of the regenerator 6 as a product CO2. In this
regard, in the above-described embodiments, since the first flow rate F1 and the second
flow rate F2 and/or the ratio F1/F2 are regulated such that the temperature of the tower
top portion of the regenerator 6 is within a specified range, the temperature of the product
CO2 recovered from the absorption solvent re 5 generation device 4 can be easily regulated
within an appropriate range by setting these values appropriately.
[0083] In some embodiments, the regulating part 60 may be configured to regulate
the ratio F1/F2 between the first flow rate F1 and the second flow rate F2 such that the
temperature T2 of the absorption solvent in the main rich solvent line 10 and downstream
10 of the second branch portion 12b is within a specified range. Alternatively, the
regulating part 60 may be configured to regulate, as well as the ratio F1/F2, the first flow
rate F1 and the second flow rate F2 such that the temperature T2 of the absorption solvent
in the main rich solvent line 10 and downstream of the second branch portion 12b is
within a specified range.
15 [0084] The regulating part 60 may regulate the ratio F1/F2, the first flow rate F1, and
the second flow rate F2 by regulating the opening degree of the first valve 14 and the
second valve 15 based on a detected temperature by the second temperature sensor 72
disposed in the main rich solvent line 10 and downstream of the second branch portion
12b.
20 [0085] In the regenerator 6, the absorption solvent from the main rich solvent line 10
is heated by gas-liquid contact with saturated steam, and CO2 released therefrom flows
into the recovery line 28 via the tower top portion. Therefore, the temperature T2 of the
absorption solvent in the main rich solvent line 10 and downstream of the second branch
portion 12b may serve as an index of the temperature of the tower top portion of the
25 regenerator 6. The higher the temperature of the absorption solvent in the main rich
solvent line 10, the higher the temperature of the tower top portion of the regenerator 6.
In this regard, in the above-described embodiments, since the first flow rate F1 and the
26
second flow rate F2 and/or the ratio F1/F2 are regulated such that the temperature of the
absorption solvent in the main rich solvent line 10 and downstream of the second branch
portion 12b is within a specified range, the temperature of the product CO2 recovered
from the absorption solvent regeneration device 4 can be easily regulated within an
appropriate 5 range by setting these values appropriately.
[0086] In some embodiments, the regulating part 60 may be configured to regulate
the ratio F1/F2 between the first flow rate F1 and the second flow rate F2 such that the
temperature T4 of the condensed water in the steam line 22 and downstream of the second
heat exchanger 26 is within a specified range. Alternatively, the regulating part 60 may
10 be configured to regulate, as well as the ratio F1/F2, the first flow rate F1 and the second
flow rate F2 such that the temperature T4 of the condensed water in the steam line 22 and
downstream of the second heat exchanger 26 is within a specified range.
[0087] The regulating part 60 may regulate the ratio F1/F2, the first flow rate F1, and
the second flow rate F2 by regulating the opening degree of the first valve 14 and the
15 second valve 15 based on a detected temperature by the fourth temperature sensor 74
disposed in a portion of the steam line 22 downstream of the second heat exchanger 26.
[0088] In the above-described embodiments, since the first flow rate F1 and the
second flow rate F2 and/or the ratio F1/F2 are regulated such that the temperature of the
condensed water in the steam line 22 and downstream of the second heat exchanger 26 is
20 within a specified range, the temperature of the steam condensed water obtained from the
absorption solvent regeneration device 4 can be easily regulated within an appropriate
range by setting these values appropriately.
[0089] In some embodiments, the regulating part 60 may be configured to regulate
the ratio F1/F2 between the first flow rate F1 and the second flow rate F2 such that the
25 temperature T1 of the absorption solvent which is an upstream side more than the second
heating exchanger 26 in the downstream portion 12c is within a specified range.
Alternatively, the regulating part 60 may be configured to regulate, as well as the ratio
27
F1/F2, the first flow rate F1 and the second flow rate F2 such that the temperature T1 of
the absorption solvent which is an upstream side more than the second heating exchanger
26 in the downstream portion 12c is within a specified range.
[0090] The regulating part 60 may regulate the ratio F1/F2, the first flow rate F1, and
the second flow rate F2 by regulating the 5 opening degree of the first valve 14 and the
second valve 15 based on a detected temperature by the first temperature sensor 71
disposed in the downstream portion 12c of the branch rich solvent line 12 and upstream
of the second heat exchanger 26.
[0091] The absorption solvent in the downstream portion 12c of the branch rich
10 solvent line 12 and upstream of the second heat exchanger 26 and the condensed water in
the steam line 22 and downstream of the second heat exchanger 26 exchange heat in the
second heat exchanger 26. Therefore, the temperature T1 of the absorption solvent in
the downstream portion 12c and upstream of the second heat exchanger 26 may serve as
an index of the temperature T4 of condensed water in the steam line 22 and downstream
15 of the second heat exchanger 26. In this regard, in the above-described embodiments,
since the first flow rate F1 and the second flow rate F2 and/or the ratio F1/F2 are regulated
such that the temperature T1 of the absorption solvent in the downstream portion 12c of
the branch rich solvent line 12 and upstream of the second heat exchanger 26 is within a
specified range, the temperature of the steam condensed water obtained from the
20 absorption solvent regeneration device 4 can be easily regulated within an appropriate
range by setting these values appropriately.
[0092] In the exemplary embodiment shown in FIG. 2, the regulating part 60 may be
configured to regulate the ratio F1/F2 between the first flow rate F1 and the second flow
rate F2 such that the temperature T5 of the absorption solvent at a position of the
25 downstream portion 12c downstream of the second heat exchanger 26 is within a specified
range. Alternatively, the regulating part 60 may be configured to regulate, as well as the
ratio F1/F2, the first flow rate F1 and the second flow rate F2 such that the temperature
28
T5 of the absorption solvent at a position of the downstream portion 12c downstream of
the second heat exchanger 26 is within a specified range.
[0093] The regulating part 60 may regulate the ratio F1/F2, the first flow rate F1, and
the second flow rate F2 by regulating the opening degree of the first valve 14 and the
second valve 15 based on a detected 5 temperature by the fifth temperature sensor 75
disposed in the downstream portion 12c and downstream of the second heat exchanger
26.
[0094] 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
10 constitutes the reboiler outlet line 20b. For example, when the flow from the
regeneration reboiler 24 is a two-phase flow 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,
15 the pipe is less likely to vibrate.
[0095] In this regard, in the above-described embodiments, as well as the flow rate
can be increased by flowing the absorption solvent (rich solvent) from the downstream
portion 12c of the branch rich solvent line 12 to the reboiler outlet line 20b, the
temperature of the absorption solvent can be regulated. Accordingly, vibration of the
20 pipe can be effectively suppressed by effectively regulating the flow state in the reboiler
outlet line 20b.
[0096] 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.
25 [0097] 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
29
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
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 5 in which the feature is strictly equal,
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
10 includes a shape with unevenness or chamfered 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.
15
30
Reference Signs List
[0098]
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
12a First branch portion
12b Second branch portion
12c Downstream portion
14 First valve
15 15 Second valve
16 Lean solvent line
17 Lean solvent pump
18 First heat exchanger
20 Reboiler line
20 20a Reboiler inlet line
20b Reboiler outlet line
22 Steam line
24 Regeneration reboiler
26 Second heat exchanger
25 28 Recovery line
30 Condenser
32 Absorbing section
31
34 Washing section
36 Chimney tray
38 Circulation line
39 Circulation pump
5 40 Demister
42 Tower top portion
44 Release section
44A First release section
44B Second release section
10 46 Chimney tray
48 Demister
50 Flow rate sensor
51 Flow rate sensor
60 Regulating part
15 61 First branch point
62 Second branch point
71 First temperature sensor
72 Second temperature sensor
73 Third temperature sensor
20 74 Fourth temperature sensor
75 Fifth temperature sensor

WE CLAIMS

1. An absorption solvent regeneration device, comprising:
a regenerator for regenerating an absorption solvent by separating CO2 from
the absorption solvent which has absorbed CO2;
a main rich 5 solvent line for supplying the absorption solvent which has
absorbed CO2 to the regenerator;
a first heating part for heating the absorption solvent flowing through the main
rich solvent line, the first heating part being disposed on the main rich solvent line;
and
10 a branch rich solvent line for supplying a part of the absorption solvent
flowing through the main rich solvent line to the regenerator, the branch rich solvent
line branching from the main rich solvent line,
wherein the branch rich solvent line includes:
a first branch portion branching from a first branch point disposed on the main
15 rich solvent line and upstream of the first heating part; and
a second branch portion branching from a second branch point disposed on
the main rich solvent line and downstream of the first heating part,
wherein the absorption solvent regeneration device further comprises a
regulating part for regulating a ratio between a first flow rate of the absorption
20 solvent flowing through the first branch portion and a second flow rate of the
absorption solvent flowing through the second branch portion.
2. The absorption solvent regeneration device according to claim 1,
wherein the regulating part is configured to regulate a flow rate of the
absorption solvent distributed from the main rich solvent line to the branch rich
25 solvent line.
3. The absorption solvent regeneration device according to claim 1 or 2,
wherein the regulating part includes at least one of a first valve, disposed on
33
the first branch portion, for regulating the first flow rate or a second valve, disposed
on the second branch portion, for regulating the second flow rate.
4. The absorption solvent regeneration device according to any one of claims 1 to 3,
wherein the regulating part is configured to regulate the ratio between the first
flow rate and the second flow rate such 5 that a temperature of a tower top portion of
the regenerator is within a specified range.
5. The absorption solvent regeneration device according to any one of claims 1 to 4,
wherein the regulating part is configured to regulate the ratio between the first
flow rate and the second flow rate such that a temperature of the absorption solvent
10 in the main rich solvent line and downstream of the second branch portion is within
a specified range.
6. The absorption solvent regeneration device according to any one of claims 1 to 5,
wherein the branch rich solvent line includes a downstream portion which is
a portion downstream of a junction point between the first branch portion and the
15 second branch portion,
wherein the absorption solvent regeneration device further comprises:
a regeneration reboiler for heating the absorption solvent extracted from the
regenerator by heat exchange with steam;
a steam line through which steam to be supplied to the regeneration reboiler
20 flows; and
a second heating part disposed on the steam line and configured to heat the
absorption solvent flowing through the downstream portion by heat exchange with
condensed water of steam after heating the absorption solvent in the regeneration
reboiler,
25 wherein the regulating part is configured to regulate the ratio between the first
flow rate and the second flow rate such that a temperature of the condensed water
in the steam line and downstream of the second heating part is within a specified
34
range.
7. The absorption solvent regeneration device according to any one of claims 1 to 6,
wherein the branch rich solvent line includes a downstream portion which is
a portion downstream of a junction point between the first branch portion and the
5 second branch portion,
wherein the absorption solvent regeneration device further comprises:
a regeneration reboiler for heating the absorption solvent extracted from the
regenerator by heat exchange with steam;
a steam line through which steam to be supplied to the regeneration reboiler
10 flows; and
a second heating part disposed on the steam line and configured to heat the
absorption solvent flowing through the downstream portion by heat exchange with
condensed water of steam after heating the absorption solvent in the regeneration
reboiler,
15 wherein the regulating part is configured to regulate the ratio between the first
flow rate and the second flow rate such that a temperature of the absorption solvent
which is an upstream side more than the second heating part in the downstream
portion is within a specified range.
8. A CO2 recovery device, comprising:
20 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
to 7,
25 wherein the main rich solvent line is configured to supply the absorption
solvent which has absorbed CO2 in the absorber to the regenerator.
9. An absorption solvent regeneration method, comprising:
35
a step of supplying an absorption solvent which has absorbed CO2 to a
regenerator via a main rich solvent line;
a step of regenerating the absorption solvent by separating CO2 from the
absorption solvent in the regenerator;
a step of heating 5 the absorption solvent flowing through the main rich solvent
line by a first heating part disposed on the main rich solvent line; and
a step of distributing a part of the absorption solvent flowing through the main
rich solvent line to a branch rich solvent line branching from the main rich solvent
line,
10 wherein the step of distributing includes distributing a part of the absorption
solvent to a first branch portion branching from a first branch point disposed on the
main rich solvent line and upstream of the first heating part and a second branch
portion branching from a second branch point disposed on the main rich solvent
line and downstream of the first heating part,
15 wherein the absorption solvent regeneration method further comprising a
regulating step of regulating a ratio between a first flow rate of the absorption
solvent flowing through the first branch portion and a second flow rate of the
absorption solvent flowing through the second branch portion.
10. The absorption solvent regeneration method according to claim 9,
20 wherein the regulating step includes regulating a flow rate of the absorption
solvent distributed from the main rich solvent line to the branch rich solvent line.
11. The absorption solvent regeneration method according to claim 9 or 10,
wherein the regulating step includes regulating the first flow rate by a first
valve disposed on the first branch portion or regulating the second flow rate by a
25 second valve disposed on the second branch portion.
12. The absorption solvent regeneration method according to any one of claims 9 to 11,
36
wherein the regulating step includes regulating the ratio between the first flow
rate and the second flow rate such that a temperature of a tower top portion of the
regenerator is within a specified range.
13. The absorption solvent regeneration method according to any one of claims 9 to 12,
wherein the regulating step 5 includes regulating the ratio between the first flow
rate and the second flow rate such that a temperature of the absorption solvent in
the main rich solvent line and downstream of the second branch portion is within a
specified range.
14. The absorption solvent regeneration method according to any one of claims 9 to 13,
10 wherein the branch rich solvent line includes a downstream portion which is
a portion downstream of a junction point between the first branch portion and the
second branch portion,
wherein the absorption solvent regeneration method further comprises:
a step of extracting the absorption solvent from the regenerator and heating
15 the absorption solvent by heat exchange with steam in a regeneration reboiler;
a step of supplying the steam to the regeneration reboiler via a steam line; and
a step of heating, in a second heating part disposed on the steam line, the
absorption solvent flowing through the downstream portion by heat exchange with
condensed water of steam after heating the absorption solvent in the regeneration
20 reboiler,
wherein the regulating step includes regulating the ratio between the first flow
rate and the second flow rate such that a temperature of the condensed water in the
steam line and downstream of the second heating part is within a specified range.
15. The absorption solvent regeneration method according to any one of claims 9 to 14,
25 wherein the branch rich solvent line includes a downstream portion which is
a portion downstream of a junction point between the first branch portion and the
second branch portion,
37
wherein the absorption solvent regeneration method further comprises:
a step of extracting the absorption solvent from the regenerator and heating
the absorption solvent by heat exchange with steam in a regeneration reboiler;
a step of supplying the steam to the regeneration reboiler via a steam line; and
a step of heating, in a second heating 5 part disposed on the steam line, the
absorption solvent flowing through the downstream portion by heat exchange with
condensed water of steam after heating the absorption solvent in the regeneration
reboiler,
wherein the regulating step includes regulating the ratio between the first flow
10 rate and the second flow rate such that a temperature of the absorption solvent which
is an upstream side more than the second heating part in the downstream portion is
within a specified range.