U.S. patent application number 12/952969 was filed with the patent office on 2011-05-26 for fossil fuel combustion thermal power system including carbon dioxide separation and capture unit.
This patent application is currently assigned to Hitachi, Ltd.. Invention is credited to Tetsuya KOSAKA, Osamu MATSUURA, Nobuyoshi MISHIMA, Takashi SUGIURA.
Application Number | 20110120130 12/952969 |
Document ID | / |
Family ID | 43616998 |
Filed Date | 2011-05-26 |
United States Patent
Application |
20110120130 |
Kind Code |
A1 |
MISHIMA; Nobuyoshi ; et
al. |
May 26, 2011 |
Fossil Fuel Combustion Thermal Power System Including Carbon
Dioxide Separation and Capture Unit
Abstract
A fossil fuel combustion thermal power system including a carbon
dioxide separation and capture unit comprising a fossil fuel
combustion thermal power system including a boiler for burning
fossil fuel and generating steam and a steam turbine including a
high-pressure turbine driven by the steam generated by the boiler
for generating power, and a carbon dioxide separation and capture
unit.
Inventors: |
MISHIMA; Nobuyoshi;
(Hitachi, JP) ; SUGIURA; Takashi; (Hitachinaka,
JP) ; MATSUURA; Osamu; (Hitachi, JP) ; KOSAKA;
Tetsuya; (Hitachi, JP) |
Assignee: |
Hitachi, Ltd.
Tokyo
JP
|
Family ID: |
43616998 |
Appl. No.: |
12/952969 |
Filed: |
November 23, 2010 |
Current U.S.
Class: |
60/660 ;
60/670 |
Current CPC
Class: |
F01K 7/22 20130101; F01K
13/00 20130101; Y02E 20/326 20130101; Y02E 20/32 20130101; F01K
7/16 20130101; F01K 17/04 20130101 |
Class at
Publication: |
60/660 ;
60/670 |
International
Class: |
F01K 13/02 20060101
F01K013/02; F01K 23/06 20060101 F01K023/06 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 25, 2009 |
JP |
2009-266939 |
Dec 25, 2009 |
JP |
2009-293717 |
Claims
1. A fossil fuel combustion thermal power system including a carbon
dioxide separation and capture unit comprising: a fossil fuel
combustion thermal power system including a boiler for burning
fossil fuel and generating steam and a steam turbine including a
high-pressure turbine driven by the steam generated by the boiler
for generating power, and a carbon dioxide separation and capture
unit including an absorption tower for absorbing and capturing
carbon dioxide included in the exhaust gas discharged from the
boiler by burning fossil fuel in the boiler of the fossil fuel
combustion thermal power system and a reproduction tower of an
absorbing solution for separating carbon dioxide from the absorbing
solution absorbing carbon dioxide by circulating the absorbing
solution between the reproduction tower and the absorption tower,
the fossil fuel combustion thermal power system including the
carbon dioxide separation and capture unit further comprising: a
back-pressure turbine driven by extraction steam extracted from the
high-pressure turbine of the fossil fuel combustion thermal power
system through an extraction pipe; a reboiler for supplying heating
steam to the reproduction tower of the carbon dioxide separation
and capture unit; a steam pipe for supplying steam flowing down
through the back-pressure turbine of the fossil fuel combustion
thermal power system to the reboiler as a heat source; an emergency
relief pipe interconnected to the extraction pipe for supplying the
extraction steam extracted from the high-pressure turbine of the
fossil fuel combustion thermal power system to the back-pressure
turbine for permitting the extraction steam flowing down through
the extraction pipe to bypass the back-pressure turbine and flow
down to a condenser; and an emergency relief valve installed on the
emergency relief pipe for controlling flow of the extraction steam
through the emergency relief pipe.
2. A fossil fuel combustion thermal power system including a carbon
dioxide separation and capture unit comprising: a fossil fuel
combustion thermal power system including a boiler for burning
fossil fuel and generating steam and a steam turbine including a
high-pressure turbine and a intermediate-pressure turbine driven by
the steam generated by the boiler for generating power, and a
carbon dioxide separation and capture unit including an absorption
tower for absorbing and capturing carbon dioxide included in the
exhaust gas discharged from the boiler by burning fossil fuel in
the boiler of the fossil fuel combustion thermal power system and a
reproduction tower of an absorbing solution for separating carbon
dioxide from the absorbing solution absorbing carbon dioxide by
circulating the absorbing solution between the reproduction tower
and the absorption tower, the fossil fuel combustion thermal power
system including the carbon dioxide separation and capture unit
further comprising: a reheat steam extraction pipe branching from a
high-temperature reheat steam pipe for supplying reheat steam
reheated by the boiler to the intermediate-pressure turbine from
the boiler of the fossil fuel combustion thermal power system; a
temperature lowering unit for lowering a temperature of the reheat
steam extracted through the reheat steam extraction pipe; a
back-pressure turbine driven by the reheat steam lowered in
temperature by the temperature lowering unit; a reboiler for
supplying heating steam to the reproduction tower of the carbon
dioxide separation and capture unit; a steam pipe for supplying the
steam flowing down through the back-pressure turbine of the fossil
fuel combustion thermal power system to the reboiler as a heat
source; a second emergency relief pipe interconnected to the reheat
steam extraction pipe for supplying the reheat steam extracted
through the reheat steam extraction pipe of the fossil fuel
combustion thermal power system to the back-pressure turbine for
permitting the reheat steam flowing down through the reheat steam
extraction pipe to bypass the back-pressure turbine and flow down
to a condenser; and a second emergency relief valve installed in
the second emergency relief pipe for controlling flow of the reheat
steam through the second emergency relief pipe.
3. A fossil fuel combustion thermal power system including a carbon
dioxide separation and capture unit comprising: a fossil fuel
combustion thermal power system including a boiler for burning
fossil fuel and generating steam and a steam turbine including a
high-pressure turbine and a intermediate-pressure turbine driven by
the steam generated by the boiler for generating power, and a
carbon dioxide separation and capture unit including an absorption
tower for absorbing and capturing carbon dioxide included in the
exhaust gas discharged from the boiler by burning fossil fuel in
the boiler of the fossil fuel combustion thermal power system and a
reproduction tower of an absorbing solution for separating carbon
dioxide from the absorbing solution absorbing carbon dioxide by
circulating the absorbing solution between the reproduction tower
and the absorption tower, the fossil fuel combustion thermal power
system including the carbon dioxide separation and capture unit
further comprising: a back-pressure turbine driven by the
extraction steam extracted from the high-pressure turbine of the
fossil fuel combustion thermal power system through a first
extraction pipe; a second steam extraction pipe for branching a
part of the exhaust steam of the intermediate-pressure turbine
supplied from the intermediate-pressure turbine of the fossil fuel
combustion thermal power system to a low-pressure turbine; a first
steam pipe for supplying the extraction steam extracted through the
second steam extraction pipe to the back-pressure turbine; a
reboiler for supplying heating steam to the reproduction tower of
the carbon dioxide separation and capture unit; a second steam pipe
for supplying the steam flowing down through the back-pressure
turbine of the fossil fuel combustion thermal power system to the
reboiler as a heat source; a first emergency relief pipe
interconnected to the first extraction pipe for supplying the
extraction steam extracted from the high-pressure turbine of the
fossil fuel combustion thermal power system to the back-pressure
turbine for permitting the extraction steam flowing down through
the first extraction pipe to bypass the back-pressure turbine and
flow down to a condenser; a first emergency relief valve installed
in the first emergency relief pipe for controlling flow of the
extraction steam through the first emergency relief pipe; a third
emergency relief pipe interconnected to the first steam pipe for
supplying the extraction steam extracted through the second steam
extraction pipe of the fossil fuel combustion thermal power system
to the back-pressure turbine for permitting the extraction steam
flowing down through the first steam pipe to bypass the
back-pressure turbine and flow down to a condenser, and a third
emergency relief valve installed in the third emergency relief pip
for controlling flow of the reheat steam through the third
emergency relief pipe.
4. The fossil fuel combustion thermal power system including a
carbon dioxide separation and capture unit according to claim 1,
further comprising: a control unit for outputting an instruction
signal for controlling the opening and closing of the emergency
relief valve on the basis of a trip signal of the carbon dioxide
separation and capture unit at the time of an urgent stop of the
carbon dioxide separation and capture unit and controlling the
extraction steam extracted through the extraction pipe of the
fossil fuel combustion thermal power system so as to pass through
the emergency relief pipe, bypass the back-pressure turbine, and
flow down to the condenser.
5. The fossil fuel combustion thermal power system including a
carbon dioxide separation and capture unit according to claim 2,
further comprising: a control unit for outputting an instruction
signal for controlling the opening and closing of the second
emergency relief valve on the basis of a trip signal of the carbon
dioxide separation and capture unit at the time of an urgent stop
of the carbon dioxide separation and capture unit and controlling
the reheat steam flowing down through the reheat steam extraction
pipe of the fossil fuel combustion thermal power system so as to
pass through the second emergency relief pipe, bypass the
back-pressure turbine, and flow down to the condenser.
6. The fossil fuel combustion thermal power system including a
carbon dioxide separation and capture unit according to claim 3,
further comprising: a control unit, in a partial load operation of
the fossil fuel combustion thermal power system, for outputting an
instruction signal for controlling the opening and closing of the
first emergency relief valve on the basis of a trip signal of the
carbon dioxide separation and capture unit at the time of an urgent
stop of the carbon dioxide separation and capture unit and
controlling the extraction steam extracted through the first
extraction pipe of the fossil fuel combustion thermal power system
so as to pass through the first emergency relief pipe, bypass the
back-pressure turbine, and flow down to the condenser, and in a
total partial load operation of the fossil fuel combustion thermal
power system, for outputting an instruction signal for controlling
the opening and closing of the third emergency relief valve and
controlling the extraction steam extracted through the second
extraction pipe of the fossil fuel combustion thermal power system
so as to pass through the third emergency relief pipe, bypass the
back-pressure turbine, and flow down to the condenser.
7. The fossil fuel combustion thermal power system including a
carbon dioxide separation and capture unit according to claim 4,
wherein: the trip signal of the carbon dioxide separation and
capture unit is a trip signal of a transfer pump for transferring
the absorbing solution between the absorption tower and the
reproduction tower of the carbon dioxide separation and capture
unit.
8. The fossil fuel combustion thermal power system including a
carbon dioxide separation and capture unit according to claim 5,
wherein: the trip signal of the carbon dioxide separation and
capture unit is a trip signal of a transfer pump for transferring
the absorbing solution between the absorption tower and the
reproduction tower of the carbon dioxide separation and capture
unit.
9. The fossil fuel combustion thermal power system including a
carbon dioxide separation and capture unit according to claim 6,
wherein: the trip signal of the carbon dioxide separation and
capture unit is a trip signal of a transfer pump for transferring
the absorbing solution between the absorption tower and the
reproduction tower of the carbon dioxide separation and capture
unit.
10. The fossil fuel combustion thermal power system including a
carbon dioxide separation and capture unit according to claim 1,
further comprising: a low-pressure turbine driven by extraction
steam sent from the high-pressure turbine to the back-pressure
turbine through the extraction pipe, and a flow path switching
valve for switching a supply destination of the extraction steam
sent from the high-pressure turbine to the back-pressure turbine
through the extraction pipe from the back-pressure turbine to the
low-pressure turbine.
11. The fossil fuel combustion thermal power system including a
carbon dioxide separation and capture unit according to claim 2,
further comprising: a low-pressure turbine driven by extraction
steam sent from the high-pressure turbine to the back-pressure
turbine through the extraction pipe, and a flow path switching
valve for switching a supply destination of the extraction steam
sent from the high-pressure turbine to the back-pressure turbine
through the extraction pipe from the back-pressure turbine to the
low-pressure turbine.
12. The fossil fuel combustion thermal power system including a
carbon dioxide separation and capture unit according to claim 3,
further comprising: a low-pressure turbine driven by extraction
steam sent from the high-pressure turbine to the back-pressure
turbine through the extraction pipe, and a flow path switching
valve for switching a supply destination of the extraction steam
sent from the high-pressure turbine to the back-pressure turbine
through the extraction pipe from the back-pressure turbine to the
low-pressure turbine.
13. The fossil fuel combustion thermal power system including a
carbon dioxide separation and capture unit according to claim 3,
further comprising: a low-pressure turbine driven by extraction
steam sent from the intermediate-pressure turbine to the
back-pressure turbine, and a flow path switching valve for
switching a supply destination of the extraction steam sent from
the intermediate-pressure turbine to the back-pressure turbine from
the back-pressure turbine to the low-pressure turbine.
Description
CLAIM OF PRIORITY
[0001] The present application claims priority from Japanese patent
application serial No. 2009-266939, filed on Nov. 25, 2009, and
Japanese patent application serial No. 2009-293717, filed on Dec.
25, 2009, the contents of which are hereby incorporated by
reference into this application.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a fossil fuel combustion
thermal power system including a carbon dioxide separation and
capture unit.
[0004] 2. Description of Related Art
[0005] As a fossil fuel combustion thermal power system including a
carbon dioxide separation and capture unit relating to the present
invention, there is a system including a PCC unit (PCC: post
combustion CO.sub.2 capture) for separating and capturing carbon
dioxide from fossil fuel, for example, the exhaust gas of a coal
combustion boiler.
[0006] In Japanese Patent 4274846, as a capture system of carbon
dioxide included in the exhaust gas of a boiler, a carbon dioxide
capture system including a steam turbine having a high-pressure
turbine, an intermediate-pressure turbine, and a low-pressure
turbine, a boiler for generating steam for driving these turbines,
a carbon dioxide absorption tower having a carbon dioxide absorbing
solution for absorbing and removing carbon dioxide from the
combustion exhaust gas of the boiler, a reproduction tower for
reproducing the carbon dioxide absorbing solution absorbing carbon
dioxide, a compressor for compressing the removed carbon dioxide, a
turbine for the compressor driven by a part of the exhaust steam
exhausted from the high-pressure turbine, a turbine for an
auxiliary unit driven by a part of the exhaust steam exhausted from
the intermediate-pressure turbine, and a supply pipe for supplying
exhaust steam exhausted from the turbine for the compressor and the
turbine for the auxiliary unit to the reboiler of the reproduction
tower as a heating source, is disclosed.
[0007] Generally, in the carbon dioxide separation and capture unit
for capturing carbon dioxide from the exhaust gas of the boiler,
the absorbing solution circulation pump is driven so as to
circulate the absorbing solution between the absorption tower and
the reproduction tower, and the carbon dioxide included in the
exhaust gas of the boiler is absorbed by the absorbing solution in
the absorption tower, and the carbon dioxide absorbed by the
absorbing solution is separated and captured by the reproduction
tower.
[0008] Namely, the carbon dioxide component in the exhaust gas of
the boiler and the absorbing solution are permitted to make contact
with each other in the absorption tower, and by a chemical reaction
(heat generation reaction) of the absorbing solution at about
40.degree. C. with the carbon dioxide in the gas, the carbon
dioxide is absorbed.
[0009] A carbon-dioxide-enriched absorbing solution at about
70.degree. C. due to the chemical reaction of the absorbing
solution with the carbon dioxide at this time leaves the absorption
tower, then exchanges heat with a reproduced absorbing solution
(called a lean absorbing solution) at about 120.degree. C. supplied
from the reproduction tower, is heated up to about 110.degree. C.,
and flows again into the absorption tower.
[0010] The enriched absorbing solution after heat exchange is
heated again to 120.degree. C. to 130.degree. C. in the
reproduction tower and separates the carbon dioxide absorbed by the
enriched absorbing solution.
[0011] The absorbing solution separating the carbon dioxide by the
reproduction tower becomes a lean absorbing solution, is introduced
again into the absorption tower, and absorbs carbon dioxide in the
exhaust gas of the boiler.
[0012] In this case, the absorbing solution in the reproduction
tower is heated so as to separate the carbon dioxide and become the
lean absorbing solution, so that the reboiler for supplying heating
steam to the reproduction tower must generate a large quantity of
steam. [0013] Patent Document 1: Japanese Patent No. 4274846
SUMMARY OF THE INVENTION
[0014] In the carbon dioxide capture system described in Japanese
Patent No. 4274846, when the pump for circulating the absorbing
solution for absorbing and separating carbon dioxide between the
absorption tower and the reproduction tower of the carbon dioxide
separation and capture unit trips from some cause and the carbon
dioxide separation and capture unit stops urgently, the destination
of exhaust steam supplied to the reboiler from the turbine for the
compressor and the turbine for the auxiliary unit which are driven
by the exhaust steam exhausted from the high-pressure turbine and
the intermediate-pressure turbine of the steam turbine is lost, so
that a problem arises that the load on the turbine for the
compressor and the turbine for the auxiliary unit is changed
greatly, and a large load change is caused to the steam turbine
plant, thus the output of the steam turbine is lowered.
[0015] An object of the present invention is to provide a fossil
fuel combustion thermal power system including a carbon dioxide
separation and capture unit capable of suppressing a load change
caused to the fossil fuel combustion thermal power system when the
carbon dioxide separation and capture unit urgently stops the
operation.
[0016] The present invention of a fossil fuel combustion thermal
power system including a carbon dioxide separation and capture unit
comprising: a fossil fuel combustion thermal power system including
a boiler for burning fossil fuel and generating steam and a steam
turbine including a high-pressure turbine driven by the steam
generated by the boiler for generating power, and a carbon dioxide
separation and capture unit including an absorption tower for
absorbing and capturing carbon dioxide included in the exhaust gas
discharged from the boiler by burning fossil fuel in the boiler of
the fossil fuel combustion thermal power system and a reproduction
tower of an absorbing solution for separating carbon dioxide from
the absorbing solution absorbing carbon dioxide by circulating the
absorbing solution between the reproduction tower and the
absorption tower,
[0017] the fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit further comprising:
a back-pressure turbine driven by extraction steam extracted from
the high-pressure turbine of the fossil fuel combustion thermal
power system through an extraction pipe; a reboiler for supplying
heating steam to the reproduction tower of the carbon dioxide
separation and capture unit; a steam pipe for supplying steam
flowing down through the back-pressure turbine of the fossil fuel
combustion thermal power system to the reboiler as a heat source;
an emergency relief pipe interconnected to the extraction pipe for
supplying the extraction steam extracted from the high-pressure
turbine of the fossil fuel combustion thermal power system to the
back-pressure turbine for permitting the extraction steam flowing
down through the extraction pipe to bypass the back-pressure
turbine and flow down to a condenser; and an emergency relief valve
installed on the emergency relief pipe for controlling flow of the
extraction steam through the emergency relief pipe.
[0018] Further, the present invention of a fossil fuel combustion
thermal power system including a carbon dioxide separation and
capture unit comprising: a fossil fuel combustion thermal power
system including a boiler for burning fossil fuel and generating
steam and a steam turbine including a high-pressure turbine and a
intermediate-pressure turbine driven by the steam generated by the
boiler for generating power, and a carbon dioxide separation and
capture unit including an absorption tower for absorbing and
capturing carbon dioxide included in the exhaust gas discharged
from the boiler by burning fossil fuel in the boiler of the fossil
fuel combustion thermal power system and a reproduction tower of an
absorbing solution for separating carbon dioxide from the absorbing
solution absorbing carbon dioxide by circulating the absorbing
solution between the reproduction tower and the absorption
tower,
[0019] the fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit further comprising:
a reheat steam extraction pipe branching from a high-temperature
reheat steam pipe for supplying reheat steam reheated by the boiler
to the intermediate-pressure turbine from the boiler of the fossil
fuel combustion thermal power system; a temperature lowering unit
for lowering a temperature of the reheat steam extracted through
the reheat steam extraction pipe; a back-pressure turbine driven by
the reheat steam lowered in temperature by the temperature lowering
unit; a reboiler for supplying heating steam to the reproduction
tower of the carbon dioxide separation and capture unit; a steam
pipe for supplying the steam flowing down through the back-pressure
turbine of the fossil fuel combustion thermal power system to the
reboiler as a heat source; a second emergency relief pipe
interconnected to the reheat steam extraction pipe for supplying
the reheat steam extracted through the reheat steam extraction pipe
of the fossil fuel combustion thermal power system to the
back-pressure turbine for permitting the reheat steam flowing down
through the reheat steam extraction pipe to bypass the
back-pressure turbine and flow down to a condenser; and a second
emergency relief valve installed in the second emergency relief
pipe for controlling flow of the reheat steam through the second
emergency relief pipe.
[0020] Further, The present invention of a fossil fuel combustion
thermal power system including a carbon dioxide separation and
capture unit comprising: a fossil fuel combustion thermal power
system including a boiler for burning fossil fuel and generating
steam and a steam turbine including a high-pressure turbine and a
intermediate-pressure turbine driven by the steam generated by the
boiler for generating power, and a carbon dioxide separation and
capture unit including an absorption tower for absorbing and
capturing carbon dioxide included in the exhaust gas discharged
from the boiler by burning fossil fuel in the boiler of the fossil
fuel combustion thermal power system and a reproduction tower of an
absorbing solution for separating carbon dioxide from the absorbing
solution absorbing carbon dioxide by circulating the absorbing
solution between the reproduction tower and the absorption
tower,
[0021] the fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit further comprising:
a back-pressure turbine driven by the extraction steam extracted
from the high-pressure turbine of the fossil fuel combustion
thermal power system through a first extraction pipe; a second
steam extraction pipe for branching a part of the exhaust steam of
the intermediate-pressure turbine supplied from the
intermediate-pressure turbine of the fossil fuel combustion thermal
power system to a low-pressure turbine; a first steam pipe for
supplying the extraction steam extracted through the second steam
extraction pipe to the back-pressure turbine; a reboiler for
supplying heating steam to the reproduction tower of the carbon
dioxide separation and capture unit; a second steam pipe for
supplying the steam flowing down through the back-pressure turbine
of the fossil fuel combustion thermal power system to the reboiler
as a heat source; a first emergency relief pipe interconnected to
the first extraction pipe for supplying the extraction steam
extracted from the high-pressure turbine of the fossil fuel
combustion thermal power system to the back-pressure turbine for
permitting the extraction steam flowing down through the first
extraction pipe to bypass the back-pressure turbine and flow down
to a condenser; a first emergency relief valve installed in the
first emergency relief pipe for controlling flow of the extraction
steam through the first emergency relief pipe; a third emergency
relief pipe interconnected to the first steam pipe for supplying
the extraction steam extracted through the second steam extraction
pipe of the fossil fuel combustion thermal power system to the
back-pressure turbine for permitting the extraction steam flowing
down through the first steam pipe to bypass the back-pressure
turbine and flow down to a condenser, and a third emergency relief
valve installed in the third emergency relief pip for controlling
flow of the reheat steam through the third emergency relief
pipe.
[0022] According to the present invention, when an operation of the
carbon dioxide separation and capture unit stops urgently, a fossil
fuel combustion thermal power system including a carbon dioxide
separation and capture unit capable of suppressing the load change
of the fossil fuel combustion thermal power system can be
realized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a schematic flow diagram showing the fossil fuel
combustion thermal power system including the carbon dioxide
separation and capture unit of the first embodiment of the present
invention,
[0024] FIG. 2 is a partial diagram showing the fossil fuel
combustion thermal power system of the first embodiment shown in
FIG. 1,
[0025] FIG. 3 is a steam I-S line diagram for explaining the
expansion lines at the rated load and partial load of the steam
turbine and back-pressure turbine of the fossil fuel combustion
thermal power system of the embodiments of the present
invention,
[0026] FIG. 4 is a schematic flow diagram showing the fossil fuel
combustion thermal power system including the carbon dioxide
separation and capture unit of the second embodiment of the present
invention,
[0027] FIG. 5 is a partial diagram showing the fossil fuel
combustion thermal power system of the second embodiment shown in
FIG. 4,
[0028] FIG. 6 is a schematic flow diagram showing the fossil fuel
combustion thermal power system including the carbon dioxide
separation and capture unit of the third embodiment of the present
invention, and
[0029] FIG. 7 is a partial diagram showing the fossil fuel
combustion thermal power system of the third embodiment shown in
FIG. 6.
[0030] FIG. 8 is a schematic flow diagram showing the fossil fuel
combustion thermal power system including the carbon dioxide
separation and capture unit of the fourth embodiment of the present
invention, and
[0031] FIG. 9 is a partial diagram showing the fossil fuel
combustion thermal power system of the fourth embodiment shown in
FIG. 8.
[0032] FIG. 10 is a schematic flow diagram showing the fossil fuel
combustion thermal power system including the carbon dioxide
separation and capture unit of the fifth embodiment of the present
invention, and
[0033] FIG. 11 is a partial diagram showing the fossil fuel
combustion thermal power system of the fifth embodiment shown in
FIG. 10.
DETAILED DESCRIPTION OF THE INVENTION
[0034] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit which is an
embodiment of the present invention will be explained below with
reference to the accompanying drawings.
Embodiment 1
[0035] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the first
embodiment of the present invention will be explained by referring
to FIGS. 1 and 2.
[0036] FIG. 1 shows the fossil fuel combustion thermal power system
including the carbon dioxide separation and capture unit of the
first embodiment of the present invention.
[0037] A fossil fuel combustion thermal power system 100 composing
the fossil fuel combustion thermal power system including the
carbon dioxide separation and capture unit of the first embodiment
shown in FIG. 1 includes a fossil fuel combustion boiler 101 for
burning fossil fuel, heating condensed water supplied from a
condenser, and generating steam at a high temperature and high
pressure and a high-pressure turbine 103 for leading and driving
the steam generated by the boiler 101 through a main steam pipe 102
from the boiler 101.
[0038] The steam decompressed due to an occurrence of power by the
high-pressure turbine 103 for flowing down through an exhaust pipe
104 of the high-pressure turbine is supplied to the boiler 101
through a low-temperature reheat steam pipe 114 and is heated again
by the boiler 101 to reheat the steam.
[0039] The system includes an intermediate-pressure turbine 116 for
leading and driving the reheat steam heated by the boiler 101
through a high-temperature reheat steam pipe 115 from the boiler
101 and the steam reduced in pressure due to an occurrence of power
by the intermediate-pressure turbine 116 for flowing down through
an exhaust pipe 117 of the intermediate-pressure turbine from the
intermediate-pressure turbine 116 is supplied to a low-pressure
turbine 118 (not drawn).
[0040] By a generator 180 driven by the high-pressure turbine 103,
intermediate-pressure turbine 116, and low-pressure turbine 118,
the output of the steam turbine is taken out as power. Further, the
numeral 175 indicates a deaerator.
[0041] In the fossil fuel combustion thermal power system 100, a
first extraction pipe 105 branching from the low-temperature reheat
steam pipe 114 for supplying the steam flowing down through the
high-temperature turbine exhaust pipe 104 of the high-pressure
turbine 103 to the boiler 101 for extracting a part of the steam
flowing down through the low-temperature reheat steam pipe 114 in
order to drive the back-pressure turbine and a back-pressure
turbine 107 driven by the steam extracted through the first
extraction pipe 105 are installed.
[0042] On the entrance side of the back-pressure turbine 107, a
back-pressure turbine control valve 106 for controlling the output
of the back-pressure turbine 107 is installed and on the exit side
of the back-pressure turbine 107, an exhaust pipe path 108 (of the
back-pressure turbine) for permitting the exhaust gas of the
back-pressure turbine via the back-pressure turbine 107 to flow
down, an exhaust pressure control valve 109 of the back-pressure
turbine installed in the exhaust pipe path 108 of the back-pressure
turbine for adjusting the pressure of the flowing exhaust gas of
the back-pressure turbine, and an exit blast pipe 110 of the
back-pressure turbine interconnected to the exhaust pipe path 108
of the back-pressure turbine for sending the exhaust gas of the
back-pressure turbine to a reboiler 120 and a reclaimer 121 which
are installed in a carbon dioxide separation and capture unit 200
which will be described later are installed.
[0043] On the back-pressure turbine 107, a back-pressure turbine
generator 113 is installed and it is structured so as to take out
the power of the back-pressure turbine 107 as electric power.
[0044] To the low-temperature reheat steam pipe 114 through which
the steam flowing down in the high-pressure turbine 103 through the
exhaust pipe 104 of the high-pressure turbine and supplied to the
boiler 101 flows, a first emergency relief pipe 112 including a
first emergency relief valve 111 is interconnected.
[0045] And, when the back-pressure turbine 107 stops operation by
some cause, the extraction steam which flows down in the
high-pressure turbine 103 through the first extraction pipe 105
branching from the low-temperature reheat steam pipe 114 and is
supplied to the back-pressure turbine 107 is structured so as to
open the first emergency relief valve 111 installed in the first
emergency relief pipe 112 and flow down into the condenser through
the first emergency relief pipe 112.
[0046] In the fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the first
embodiment shown in FIG. 1, the fossil fuel combustion thermal
power system 100 and the carbon dioxide separation and capture unit
200 for separating and capturing the carbon dioxide included in the
exhaust gas of the boiler discharged from the boiler 101 of the
fossil fuel combustion thermal power system 100 by burning fossil
fuel are installed.
[0047] In the carbon dioxide separation and capture unit 200 shown
in FIG. 1, the boiler exhaust gas including carbon dioxide which is
discharged from the boiler 101 and is branched and supplied from a
boiler exhaust gas system pipe 171 flows down through a boiler
exhaust gas pipe 140, is boosted by a boiler exhaust gas boost fan
141 installed in the boiler exhaust gas pipe 140, then is supplied
to and cooled by a boiler exhaust gas cooler 142, and is supplied
to an absorption tower 126 for absorbing carbon dioxide gas from
the boiler exhaust gas cooler 142 by the absorbing solution.
[0048] The carbon dioxide gas included in the boiler exhaust gas is
absorbed by the absorbing solution in the absorption tower 126 and
the processed gas which is boiler exhaust gas including no carbon
dioxide is supplied to a chimney 146 from the absorption tower 126
through an exit boiler exhaust gas pipe 145 of the absorption tower
and is discharged from the chimney 146 into the atmosphere.
[0049] Further, among the boiler exhaust gas including carbon
dioxide supplied from the boiler 101 through the boiler exhaust gas
system pipe 171, the boiler exhaust gas not supplied to the
absorption tower 126, by a valve opening operation of a bypass
butterfly valve 143 installed on a bypass gas pipe 144 for
bypassing the carbon dioxide separation and capture unit 200, is
directly led to the chimney 146 through the bypass gas pipe
144.
[0050] The enriched absorbing solution absorbing carbon dioxide gas
included in the boiler exhaust gas supplied from the boiler 101 in
the absorption tower 126 and including much carbon dioxide is
boosted by an enriched absorbing solution transfer pump 127
installed in the supply path of the absorbing solution for
supplying the absorbing solution of the absorption tower 126 to a
reproduction tower 123, is supplied to an absorbing solution heat
exchanger 128 similarly installed in the supply path of the
absorbing solution, is heated by the absorbing solution heat
exchanger 128, and then is supplied to the reproduction tower
123.
[0051] The enriched absorbing solution supplied from the absorption
tower 126 to the reproduction tower 123 is heated by supplying
vapor generated by being heated by the back-pressure turbine
exhaust steam supplied to the reboiler 120 and reclaimer 121 as a
heat source to the reproduction tower 123 from the reboiler 120 and
reclaimer 121 and the carbon oxide gas absorbed by the enriched
absorbing solution in the reproduction tower 123 is separated from
the enriched absorbing solution.
[0052] By heating by the vapor supplied from the reboiler 120, the
carbon dioxide separated from the enriched absorbing solution in
the reproduction tower 123 is discharged from the reproduction
tower 123, though it is cooled by an exit gas cooler 131 installed
on the exit side of the reproduction tower 123 and then is supplied
to a reflux drum 132 for separating moisture, and the moisture
included in the carbon dioxide gas is separated, and only the
carbon oxide gas is supplied to and stored in a carbon dioxide
liquefying and storing facility (not drawn) from the reflux drum
132 through a carbon dioxide gas exhaust pipe 147.
[0053] Further, the moisture separated by the reflux drum 132 is
structured so as to be boosted by a reflux drum pump 133 and be
returned to the reproduction tower 123.
[0054] And, a part of the absorbing solution in the reproduction
tower 123 is pulled out through an absorbing solution pull-out pipe
124 in the reproduction tower and is branched and supplied to the
reboiler 120 and reclaimer 121 and it is heated by the reboiler 120
to which the back-pressure turbine exhaust steam flowing down
through the back-pressure turbine 107 driven by the heating steam
extracted from the steam turbine cycle of the fossil fuel
combustion thermal power system 100, that is, the extraction steam
extracted from the high-pressure turbine 103 is supplied as a heat
source.
[0055] Further, the reclaimer 121 is a cleaning unit of the
absorbing solution for heating the absorbing solution by using the
back-pressure turbine exhaust steam flowing down through the
back-pressure turbine 107 as a heat source, separating impurities
included in the absorbing solution, and discharging them out of the
system.
[0056] The heating steam necessary to heat the reboiler 120 and
reclaimer 121 is obtained by sending the back-pressure turbine
exhaust steam flowing down through the back-pressure turbine 107
composing the fossil fuel combustion thermal power system 100 to
the reboiler 120 and reclaimer 121 through the back-pressure
turbine exhaust pipe 110.
[0057] The absorbing solution separating carbon dioxide by heating
the absorbing solution in the reproduction tower 123 is boosted by
a lean absorbing solution transfer pump 129 installed in the return
path of the absorbing solution for returning the absorbing solution
from the reproduction tower 123 to the absorption tower 126, is
supplied to a lean absorbing solution cooler 130 similarly
installed in the return path of the absorbing solution, is cooled
by the lean absorbing solution cooler 130, and then is returned to
the absorption tower 126, thus the absorbing solution is circulated
between the absorption tower 126 and the reproduction tower
123.
[0058] And, the system is structured so as to supply the
back-pressure turbine exhaust steam flowing down from the
back-pressure turbine 107 through the back-pressure turbine exhaust
pipe 110 to the reboiler 120 and reclaimer 121 as a heat source,
indirectly heat the absorbing solution pulled out from the
reproduction tower 123 through the absorbing solution pull-out pipe
124 in the reproduction tower by the reboiler 120, generate clean
steam at a desired temperature and pressure, and supply the
generated steam to the reproduction tower 123 through a steam pipe
125 at the reboiler exit.
[0059] On the exit blast pipe 110 of the back-pressure turbine on
the upstream side of the reboiler 120 and reclaimer 121, a reboiler
heating steam pressure control valve 134 and a reclaimer heating
steam pressure control valve 135 are installed, thus the flow rate
of the back-pressure turbine exhaust steam supplied to the reboiler
120 is adjusted so as to control the steam generated by the
reboiler 120 to a desired temperature and pressure.
[0060] Further, on the downstream side of the reboiler 120 and
reclaimer 121, a boiler and a reclaimer heating steam drain pipe
122 for leading the back-pressure turbine exhaust steam which is
used by the reboiler 120 and reclaimer 121 as a heat source and is
lowered in temperature to the drain capture system of the turbine
condensate system are arranged.
[0061] FIG. 2 is a partial diagram showing the portion of the
fossil fuel combustion thermal power system 100 of the fossil fuel
combustion thermal power system including the carbon dioxide
separation and capture unit of the first embodiment shown in FIG.
1.
[0062] In the fossil fuel combustion thermal power system 100 of
this embodiment shown in FIG. 2, the first emergency relief pipe
112 including the first emergency relief valve 111 interconnected
to the low-temperature reheat steam pipe 114 through which the
steam flowing down from the high-pressure turbine 103 through the
exhaust pipe 104 of the high-pressure turbine flows for permitting
the steam flowing into the low-temperature reheat steam pipe 114 to
bypass the back-pressure turbine 107 and to be discharged to a
condenser (not shown) is arranged.
[0063] Further, there is a control unit 300 installed and by the
turbine control unit 300, the operation of the back-pressure
turbine 107 is controlled.
[0064] Namely, by an instruction signal of the control unit 300,
the opening angle of a first back-pressure turbine control valve
106 is adjusted and the flow rate of steam supplied to the
back-pressure turbine 107 is controlled. Further, by the
instruction signal of the control unit 300, the opening angle of a
back-pressure turbine exhaust pressure regulating valve 109 is
adjusted and the pressure of the back-pressure turbine exhaust
steam which flows down in the back-pressure turbine 107, flows in
the exit blast pipe 110 of the back-pressure turbine on the
downstream side of the back-pressure turbine exhaust pressure
regulating valve 109, and is supplied to the reboiler 120 is
controlled.
[0065] On the other hand, when the main unit of the carbon dioxide
separation and capture unit 200 trips by some cause, for example,
when the enriched absorbing solution transfer pump 127 for
transferring the absorbing solution or the lean absorbing solution
transfer pump 129 trips and the operation of the carbon dioxide
separation and capture unit 200 stops urgently, the surplus steam
(in the normal operation, from the back-pressure turbine 107 to the
reboiler 120, the back-pressure turbine exhaust steam flowing down
in the back-pressure turbine 107 is supplied as a heat source)
supplied from the fossil fuel combustion thermal power system 100
to the carbon dioxide separation and capture unit 200 is permitted
to bypass the back-pressure turbine 107 and to shift to the
condenser through the first emergency relief pipe 112 including the
first emergency relief valve 111.
[0066] The steam quantity required by the reboiler 120 is far
larger than the steam quantity required by the reclaimer 121 and is
equivalent to about 15% to 20% of the total quantity of evaporation
of the boiler. Therefore, at the time of urgent stop of the carbon
dioxide separation and capture unit 200, in response to an urgent
reduction of the steam quantity supplied to the reboiler 120, the
urgent relief system composed of the first emergency relief pipe
112 including the first emergency relief valve 111 for permitting
the surplus steam to flow down into the condenser can effectively
fulfill the surplus steam urgent relief function.
[0067] In the fossil fuel combustion thermal power system 100 shown
in FIG. 2, the control unit 300 for controlling the operation of
the back-pressure turbine 107 and the operation of the first
emergency relief valve 111 installed in the first emergency relief
pipe 112 for shifting the surplus steam to the condenser at the
time of urgent stop of the carbon dioxide separation and capture
unit 200 is installed.
[0068] And, when the enriched absorbing solution transfer pump 127
which is a main unit of the carbon dioxide separation and capture
unit 200 or the lean absorbing solution transfer pump 129 trips,
and the operation of the carbon dioxide separation and capture unit
200 stops urgently, and the steam supplied from the steam turbine
cycle of the fossil fuel combustion thermal power system 100 to the
reboiler 120 is required to stop immediately, on the basis of a
trip signal 127a of the enriched absorbing solution transfer pump
127 or a trip signal 129a of the lean absorbing solution transfer
pump 129 which are input from the sensors respectively installed in
the enriched absorbing solution transfer pump 127 and the lean
absorbing solution transfer pump 129, the urgent stop of the carbon
dioxide separation and capture unit 200 is detected by the control
unit 300, and to stop the operation of the back-pressure turbine
107, the first back-pressure turbine control valve 106 installed on
the entrance side of the back-pressure turbine 107 is completely
closed by the instruction signal from the control unit 300, and the
steam flowing into the back-pressure turbine 107 is
interrupted.
[0069] And, simultaneously, by the instruction signal from the
control unit 300, the first emergency relief valve 111 is opened,
and the surplus steam flowing in the back-pressure turbine 107
through the low-temperature reheat steam pipe 114 is switched so as
to bypass the back-pressure turbine 107 through the first emergency
relief pipe 112 interconnected to the low-temperature reheat steam
pipe 114 and flow down into the condenser.
[0070] The aforementioned control operation is performed under the
control of the control unit 300, thus the load change of the boiler
101 and steam turbine due to the surplus steam caused by the urgent
stop of the carbon dioxide separation and capture unit 200 is
suppressed, so that even at the time of urgent stop of the carbon
dioxide separation and capture unit 200, the stable operation of
the fossil fuel combustion thermal power system 100 can be
continued.
[0071] The surplus steam flowing down to the condenser, thereafter,
is operated so as to adjust the opening angle of the first
emergency relief valve 111 and decrease the flow rate.
[0072] Thereafter, in accordance with the flow rate reduction
operation of the surplus steam flowing down to the condenser via
the first emergency relief pipe 112 by the control unit 300, an
operation of reducing the quantity of evaporation of the vapor
generated in the boiler 101 in response to the reduction in the
steam quantity supplied to the reboiler 120 of the carbon dioxide
separation and capture unit 200 from the fossil fuel combustion
thermal power system 100 is also transferred.
[0073] On the other hand, the fossil fuel combustion thermal power
system 100 and the carbon dioxide separation and capture unit 200
are generally installed away from each other, so that the length of
the exit blast pipe 110 of the back-pressure turbine for supplying
the back-pressure turbine exhaust steam of the back-pressure
turbine 107 to the reboiler 120 is increased. Further, the steam
quantity of the back-pressure turbine exhaust steam is large and
the pipe aperture is also large, so that the storage of steam in
the exit blast pipe 110 of the back-pressure turbine cannot be
ignored.
[0074] Therefore, in this embodiment, at the position of the exit
blast pipe 110 of the back-pressure turbine on the upstream side in
the vicinity of the reboiler 120 or reclaimer 121 of the carbon
dioxide separation and capture unit 200, the reboiler entrance
pressure regulating valve 134 and reclaimer entrance pressure
regulating valve 135 are respectively installed on the exit blast
pipe 110 of the back-pressure turbine, and can thereby respond by
adjusting the opening angles of the reboiler entrance pressure
regulating valve 134 and reclaimer entrance pressure regulating
valve 135 by a control signal from the control unit 300.
[0075] FIG. 3, with respect to the steam turbine including the
high-pressure steam turbine 103, intermediate-pressure turbine 116,
and low-pressure turbine 118 composing the fossil fuel combustion
thermal power system including the carbon dioxide separation and
capture unit of the first embodiment of the present invention,
shows the steam I-S line diagram (steam enthalpy I-steam entropy S
line diagram), wherein the turbine steam expansion lines indicating
respectively the expansion line at the rated load of a load of 100%
with a thick solid line and the expansion line at the partial load
of a load of 50% with a thick alternate long and short dash line
and the expansion lines indicating respectively those at the rated
load and partial load of the back-pressure turbine 107 with thick
dashed lines are described.
[0076] As shown in the steam I-S line diagram in FIG. 3, for the
extraction steam supplied to the back-pressure turbine 107 through
the first extraction pipe 105 branched from the low-temperature
reheat steam pipe 114 through which the steam flowing down in the
high-pressure turbine 103 of the steam turbine and supplied to the
boiler 101 flows, the flow rate thereof is adjusted by the
operation of the first back-pressure turbine control valve 106,
thus the output of the back-pressure turbine 107 is controlled.
[0077] And, the exhaust pressure of the back-pressure turbine 107
is set to a pressure of about 0.5 MPa which is necessary to
generate vapor at a desired temperature and pressure by the
reboiler 120 installed in the carbon dioxide separation and capture
unit 200 in consideration of a pressure loss of about 0.1 MPa by
the pipe and valve, thus the pressure of the back-pressure turbine
exhaust steam is adjusted to about 0.6 MPa.
[0078] The locus of the expansion line of the back-pressure turbine
107 under this condition is indicated by a thick dashed line in the
steam I-S line diagram shown in FIG. 3.
[0079] The steam expanding and working in the back-pressure turbine
107 and flowing down in the back-pressure turbine 107 passes
through the back-pressure turbine exhaust pipe 108 and the
back-pressure turbine exhaust pressure regulating valve 109 and is
supplied to the reboiler 120 or reclaimer 121 of the carbon dioxide
separation and capture unit 200 as a heat source through the
back-pressure turbine exhaust pipe 110.
[0080] And, in the fossil fuel combustion thermal power system
including the carbon dioxide separation and capture unit of the
first embodiment, as shown in the steam I-S line diagram in FIG. 3,
if the steam turbine transfers from the rated main steam pressure
(25 MPa) of the rated load operation, for example, to the partial
load operation of a load of 50%, the main steam pressure is reduced
from the rated main steam pressure (25 MPa) to the 50%-load steam
pressure (12.5 MPa), though the main steam temperature is kept
almost constant even if the rated load operation is changed to the
partial load operation.
[0081] In correspondence with the reduction in the main steam
pressure aforementioned, the pressure of the steam which flows down
in the high-pressure turbine 103 through the high-pressure turbine
exhaust pipe 104 in the partial load operation and is supplied to
the low-temperature reheat steam pipe 114 lowers, though the steam
supplied to the low-temperature reheat steam pipe 114 shows the
situation that the steam under the condition of a pressure of about
0.5 MPa and a temperature of about 170.degree. C. required by the
reboiler 120 of the carbon dioxide separation and capture unit 200
to generate steam is sufficiently ensured.
[0082] Simultaneously, the steam flowing down in the exit blast
pipe 110 of the back-pressure turbine from the low-temperature
reheat steam pipe 114 via the back-pressure turbine 107 and
reaching the reboiler 120 is sufficiently away from the steam
saturation line indicated by a thin line on the lower part of FIG.
3 and the situation that the fault that the steam is drained during
flowing from the back-pressure turbine 107 to the exit blast pipe
110 of the back-pressure turbine is avoided is indicated.
[0083] According to the embodiment of the present invention
aforementioned, when the carbon dioxide separation and capture unit
stops urgently, a fossil fuel combustion thermal power system
including a carbon dioxide separation and capture unit capable of
suppressing the load change of the fossil fuel combustion thermal
power system can be realized.
Embodiment 2
[0084] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the second
embodiment of the present invention will be explained by referring
to FIGS. 4 and 5.
[0085] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the second
embodiment which is this embodiment is common in the basic
constitution to the fossil fuel combustion thermal power system
including the carbon dioxide separation and capture unit of the
first embodiment explained previously. Therefore, the explanation
of the constitution common to the two is omitted and only the
different portions will be explained below.
[0086] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the second
embodiment shown in FIG. 4 includes the fossil fuel combustion
thermal power system 100 composing the steam turbine heat cycle and
the carbon dioxide separation and capture unit 200 for separating
and capturing carbon dioxide from the boiler exhaust gas.
[0087] The fossil fuel combustion thermal power system 100 is
structured so as to extract a part of high-temperature reheat steam
through a high-temperature reheat steam extraction pipe 150
branching from the middle of the high-temperature reheat steam pipe
115 for supplying the high-temperature reheat steam from the boiler
101 to the intermediate-pressure turbine 116 and supply the
extracted high-temperature reheat steam to a high-temperature
reheat steam extraction temperature lowering unit 151.
[0088] In the high-temperature reheat steam extraction temperature
lowering unit 151, separately, the high-temperature reheat steam is
lowered in temperature by cold water led via a high-temperature
reheat steam extraction temperature lowering unit spray valve 152,
then is supplied through a second extraction pipe 153 arranged on
the exit side of the temperature lowering unit 151, and is
introduced to the back-pressure turbine 107 from a second
back-pressure turbine control valve 154.
[0089] The reheat steam introduced to the back-pressure turbine 107
through the high-temperature reheat steam extraction pipe 150
expands and works in the back-pressure turbine 107 and contributes
to power generation. And, the steam after flowing down in the
back-pressure turbine 107 is structured so as to pass through the
back-pressure turbine exhaust pipe path 108 and the back-pressure
turbine exhaust pressure regulating valve 109 from the
back-pressure turbine 107 and to be supplied to the reboiler 120 or
reclaimer 121 installed in the carbon dioxide separation and
capture unit 200 as a heat source through the back-pressure turbine
exhaust pipe 110.
[0090] On the other hand, in the fossil fuel combustion thermal
power system 100, if the steam turbine transfers to an operation of
reducing the load from the rated load operation to the partial load
operation, even though the high-temperature reheat steam pressure
of the reheat steam supplied to the intermediate-pressure turbine
116 from the boiler 101 through the high-temperature reheat steam
pipe 115 is reduced, the high-temperature reheat steam temperature
is kept almost constant even if the rated load operation is changed
to the partial load operation.
[0091] And, when the steam turbine of the fossil fuel combustion
thermal power system 100 is transferred from the rated load
operation to the partial load operation, a part of the
high-temperature reheat steam supplied from the boiler 101 to the
intermediate-pressure turbine 116 is branched from the
high-temperature reheat steam pipe 115 and is supplied to the
high-temperature reheat steam extraction temperature lowering unit
151 through the high-temperature reheat steam extraction pipe
150.
[0092] And, the high-temperature reheat steam extraction
temperature lowering unit 151 is structured so as to separately
lower the temperature of the high-temperature reheat steam by cold
water led from the high-temperature reheat steam extraction
temperature lowering unit spray valve 152 down to the temperature
required by the reboiler 120 or reclaimer 121 of the carbon dioxide
separation and capture unit 200 as a heat source which will be
described later and to introduce the reheat steam lowered in
temperature to the back-pressure turbine 107 via the second
extraction pipe 153 and second back-pressure turbine control valve
154.
[0093] Further, that the system is structured so as to supply the
back-pressure turbine exhaust steam flowing down from the
back-pressure turbine 107 to the reboiler 120 and reclaimer 121
installed in the carbon dioxide separation and capture unit 200 as
a heat source, indirectly heat the absorbing solution pulled out
from the reproduction tower 123 through the absorbing solution
pull-out pipe 124 in the reproduction tower by the reboiler 120 and
reclaimer 121, generate clean steam at a desired temperature and
pressure, and supply the generated steam to the reproduction tower
123 through the steam pipe 125 at the reboiler exit is similar to
the fossil fuel combustion thermal power system including the
carbon dioxide separation and capture unit of the first embodiment,
so the explanation of the carbon dioxide separation and capture
unit 200 will be omitted.
[0094] FIG. 5 is a partial diagram showing the portion of the
fossil fuel combustion thermal power system 100 of the fossil fuel
combustion thermal power system including the carbon dioxide
separation and capture unit of the second embodiment shown in FIG.
4.
[0095] In the fossil fuel combustion thermal power system 100 of
this embodiment shown in FIG. 5, a second emergency relief pipe 156
including a second emergency relief valve 155 interconnected to the
second extraction pipe 153 for permitting the steam flowing in the
second extraction pipe 153 to bypass the back-pressure turbine 107
and discharge it to a condenser (not drawn) is arranged.
[0096] In the fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit having the
aforementioned constitution, the high-temperature reheat steam can
be supplied to the reboiler 120 of the carbon dioxide separation
and capture unit, so that the temperature of the absorbing solution
in the reproduction tower 123 can be raised higher.
[0097] When the main unit of the carbon dioxide separation and
capture unit 200 trips from some cause, for example, when the
enriched absorbing solution transfer pump 127 for transferring the
absorbing solution or the lean absorbing solution transfer pump 129
trips and the operation of the carbon dioxide separation and
capture unit 200 stops urgently, the surplus steam (in the normal
operation, from the back-pressure turbine 107 to the reboiler 120,
the back-pressure turbine exhaust steam flowing down in the
back-pressure turbine 107 is supplied as a heat source) supplied
from the fossil fuel combustion thermal power system 100 to the
carbon dioxide separation and capture unit 200 is permitted to
bypass the back-pressure turbine 107 and to shift to the condenser
through the second emergency relief pipe 156 including the second
emergency relief valve 155.
[0098] In the fossil fuel combustion thermal power system 100 shown
in FIG. 5, a control unit 400 for controlling the operation of the
back-pressure turbine 107 and the operation of the second emergency
relief valve 155 installed in the second emergency relief pipe 156
for shifting the surplus steam to the condenser at the time of an
urgent stop of the carbon dioxide separation and capture unit 200
is installed.
[0099] And, when the enriched absorbing solution transfer pump 127
or the lean absorbing solution transfer pump 129 which are main
units of the carbon dioxide separation and capture unit 200 trips,
and the operation of the carbon dioxide separation and capture unit
200 stops urgently, and the steam supplied from the steam turbine
cycle of the fossil fuel combustion thermal power system 100 to the
reboiler 120 is required to stop immediately, on the basis of a
trip signal 127a of the enriched absorbing solution transfer pump
127 or a trip signal 129a of the lean absorbing solution transfer
pump 129 which are input from the sensors respectively installed in
the enriched absorbing solution transfer pump 127 and the lean
absorbing solution transfer pump 129, the urgent stop of the carbon
dioxide separation and capture unit 200 is detected by the control
unit 400, and to stop the operation of the back-pressure turbine
107, the second back-pressure turbine control valve 154 installed
on the entrance side of the back-pressure turbine 107 is completely
closed by the instruction signal from the control unit 400, and the
steam flowing into the back-pressure turbine 107 is
interrupted.
[0100] And, simultaneously, by the instruction signal from the
control unit 400, the second emergency relief valve 155 is opened,
and the surplus steam flowing in the back-pressure turbine 107
through the second extraction pipe 153 is switched so as to bypass
the back-pressure turbine 107 through the second emergency relief
pipe 156 interconnected to the second extraction pipe 153 and flow
down into the condenser.
[0101] The aforementioned control operation is performed under the
control of the control unit 400, thus the load change of the boiler
101 and steam turbine due to the surplus steam caused by the urgent
stop of the carbon dioxide separation and capture unit 200 is
suppressed, so that even at the time of urgent stop of the carbon
dioxide separation and capture unit 200, the stable operation of
the fossil fuel combustion thermal power system 100 can be
continued.
[0102] The surplus steam flowing down to the condenser, thereafter,
is operated so as to adjust the opening angle of the second
emergency relief valve 155 and decrease the flow rate.
[0103] Thereafter, in accordance with the flow rate reduction
operation of the surplus steam flowing down to the condenser via
the second emergency relief pipe 156 by the control unit 400, an
operation of reducing the quantity of evaporation of the vapor
generated in the boiler 101 in response to the reduction in the
steam quantity supplied to the reboiler 120 of the carbon dioxide
separation and capture unit 200 from the fossil fuel combustion
thermal power system 100 is also transferred.
[0104] According to the embodiment of the present invention
aforementioned, when the carbon dioxide separation and capture unit
stops urgently, a fossil fuel combustion thermal power system
including a carbon dioxide separation and capture unit capable of
suppressing the load change of the fossil fuel combustion thermal
power system can be realized.
Embodiment 3
[0105] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the third
embodiment of the present invention will be explained by referring
to FIG. 6.
[0106] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the third
embodiment which is this embodiment is common in the basic
constitution to the fossil fuel combustion thermal power system
including the carbon dioxide separation and capture unit of the
first embodiment explained previously. Therefore, the explanation
of the constitution common to the two is omitted and only the
different portions will be explained below.
[0107] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit shown in FIG. 6
includes the fossil fuel combustion thermal power system 100
composing the steam turbine heat cycle and the carbon dioxide
separation and capture unit 200 for separating and capturing carbon
dioxide from the boiler exhaust gas.
[0108] In the fossil fuel combustion thermal power system 100, the
first extraction pipe 105 branching from the low-temperature reheat
steam pipe 114 for supplying the steam flowing down through the
high-temperature turbine exhaust pipe 104 of the high-pressure
turbine 103 to the boiler 101 for extracting a part of the steam
flowing down through the low-temperature reheat steam pipe 114 in
order to drive the back-pressure turbine and the back-pressure
turbine 107 driven by the steam extracted through the first
extraction pipe 105 are installed and on the entrance side of the
back-pressure turbine 107, the back-pressure turbine control valve
106 for controlling the output of the back-pressure turbine 107 is
installed.
[0109] Furthermore, the system is structured so that a part of the
steam which flows down through the intermediate-pressure turbine
116 and is supplied from the intermediate-pressure turbine exhaust
pipe 117 to the low-temperature turbine 118 (not drawn) is
extracted through a intermediate-pressure turbine exhaust portion
extraction pipe 160 and the extracted steam through a third
extraction pipe 161 at the entrance of the back-pressure turbine
interconnected to the intermediate-pressure turbine exhaust portion
extraction pipe 160 is introduced to the back-pressure turbine 107
via a second back-pressure turbine control valve 162 installed on
the entrance side of the back-pressure turbine 107.
[0110] In the fossil fuel combustion thermal power system 100 of
this embodiment shown in FIG. 7, the first emergency relief pipe
112 including the first emergency relief valve 111 interconnected
to the low-temperature reheat steam pipe 114 through which the
steam flowing down from the high-pressure turbine 103 through the
exhaust pipe 104 of the high-pressure turbine flows for permitting
the steam flowing into the low-temperature reheat steam pipe 114 to
bypass the back-pressure turbine 107 and to be discharged to a
condenser (not shown) is arranged.
[0111] Furthermore, in the third extraction pipe 161 at the
entrance of the back-pressure turbine, a third emergency relief
pipe 164 for shifting the extraction steam flowing down in the
third extraction pipe 161 at the entrance of the back-pressure
turbine to the condenser is arranged and a third emergency relief
valve 163 for controlling the down-flow of the steam is arranged on
the third emergency relief pipe 164.
[0112] Further, the carbon dioxide separation and capture unit 200
is similar to that of the first embodiment, so the explanation is
omitted.
[0113] In the fossil fuel combustion thermal power system 100, when
the steam turbine transfers from the rated load operation to the
partial load operation, the steam pressure of the exhaust steam of
the intermediate-pressure turbine 116 is reduced, so that a system
of extracting steam from the intermediate-pressure turbine exhaust
pipe 117 and supplying the intermediate-pressure turbine exhaust
steam to the back-pressure turbine 107 through the
intermediate-pressure turbine exhaust portion extraction pipe 160,
the third extraction pipe 161 at the entrance of the back-pressure
turbine, and the second back-pressure turbine control valve 162 is
switched, and a system of supplying the high-pressure steam flowing
down into the low-temperature reheat steam pipe 114 from the
high-pressure turbine 103 to the back-pressure turbine 107 through
the first extraction pipe 105 and the back-pressure turbine control
valve 106 is switched, thus the steam pressure necessary to drive
the back-pressure turbine 107 is ensured.
[0114] In the fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit having the
aforementioned constitution, during the rated load operation, the
exhaust steam of the intermediate-pressure turbine 116 can be
supplied to the back-pressure turbine 107, so that compared with
the constitution of supplying only the exhaust steam of the
high-pressure turbine 103 to the back-pressure turbine 107, the
output reduction of the steam turbine can be suppressed
effectively.
[0115] When the main unit of the carbon dioxide separation and
capture unit 200 trips from some causes, for example, when the
enriched absorbing solution transfer pump 127 or the lean absorbing
solution transfer pump 129 for transferring the absorbing solution
trips and the operation of the carbon dioxide separation and
capture unit 200 stops urgently, the surplus steam (in the normal
operation, from the back-pressure turbine 107 to the reboiler 120,
the back-pressure turbine exhaust steam flowing down in the
back-pressure turbine 107 is supplied as a heat source) supplied
from the fossil fuel combustion thermal power system 100 to the
carbon dioxide separation and capture unit 200 is permitted to
bypass the back-pressure turbine 107 and to shift to the condenser
through the first emergency relief pipe 112 including the first
emergency relief valve 111 or to shift to the condenser through the
third emergency relief pipe 164 including the third emergency
relief valve 163.
[0116] In the fossil fuel combustion thermal power system 100 shown
in FIG. 7, a control unit 500 for controlling the operation of the
back-pressure turbine 107, the operation of the first emergency
relief valve 111 installed in the first emergency relief pipe 112
for shifting the surplus steam to the condenser at the time of an
urgent stop of the carbon dioxide separation and capture unit 200,
and the operation of the third emergency relief valve 163 installed
in the third emergency relief pipe 164 is installed.
[0117] And, when the enriched absorbing solution transfer pump 127
or the lean absorbing solution transfer pump 129 which are main
units of the carbon dioxide separation and capture unit 200 trips,
and the operation of the carbon dioxide separation and capture unit
200 stops urgently, and the steam supplied from the steam turbine
cycle of the fossil fuel combustion thermal power system 100 to the
reboiler 120 is required to stop immediately, on the basis of a
trip signal 127a of the enriched absorbing solution transfer pump
127 or a trip signal 129a of the lean absorbing solution transfer
pump 129 which are input from the sensors respectively installed in
the enriched absorbing solution transfer pump 127 and the lean
absorbing solution transfer pump 129, the urgent stop of the carbon
dioxide separation and capture unit 200 is detected by the control
unit 500, and to stop the operation of the back-pressure turbine
107, the first back-pressure turbine control valve 106 installed on
the entrance side of the back-pressure turbine 107 is completely
closed by the instruction signal from the control unit 500, and the
steam flowing into the back-pressure turbine 107 is
interrupted.
[0118] And, simultaneously, when the steam turbine of the fossil
fuel combustion thermal power system 100 is in the rated load
operation, by the instruction signal from the control unit 500, the
third emergency relief valve 163 is opened, and the surplus steam
flowing in the back-pressure turbine 107 through the
intermediate-pressure turbine exhaust portion extraction pipe 160
is switched so as to bypass the back-pressure turbine 107 through
the third emergency relief pipe 164 interconnected to the
intermediate-pressure turbine exhaust portion extraction pipe 160
and flow down into the condenser.
[0119] Further, when the steam turbine of the fossil fuel
combustion thermal power system 100 is in the partial load
operation, by the instruction signal from the control unit 500, the
first emergency relief valve 111 is opened, and the surplus steam
flowing in the back-pressure turbine 107 through the
low-temperature reheat steam pipe 114 is switched so as to bypass
the back-pressure turbine 107 through the first emergency relief
pipe 112 interconnected to the low-temperature reheat steam pipe
114 and flow down into the condenser.
[0120] The aforementioned control operation is performed under the
control of the control unit 500, thus the load change of the boiler
101 and steam turbine due to the surplus steam caused by the urgent
stop of the carbon dioxide separation and capture unit 200 is
suppressed, so that even at the time of urgent stop of the carbon
dioxide separation and capture unit 200, the stable operation of
the fossil fuel combustion thermal power system 100 can be
continued.
[0121] The surplus steam flowing down to the condenser, thereafter,
is operated so as to adjust the opening angle of the first
emergency relief valve 111 or the third emergency relief valve 163
and decrease the flow rate.
[0122] Thereafter, in accordance with the flow rate reduction
operation of the surplus steam flowing down to the condenser via
the first emergency relief pipe 112 or the third emergency relief
pipe 164 by the control unit 500, an operation of reducing the
quantity of evaporation of the vapor generated in the boiler 101 in
response to the reduction in the steam quantity supplied to the
reboiler 120 of the carbon dioxide separation and capture unit 200
from the fossil fuel combustion thermal power system 100 is also
transferred.
[0123] Also by the embodiment of the present invention
aforementioned, even when the carbon dioxide separation and capture
unit stops urgently from some cause, a fossil fuel combustion
thermal power system including a carbon dioxide separation and
capture unit capable of suppressing the load change of the fossil
fuel combustion thermal power system can be realized.
[0124] According to the embodiment of the present invention
aforementioned, when the carbon dioxide separation and capture unit
stops urgently, a fossil fuel combustion thermal power system
including a carbon dioxide separation and capture unit capable of
suppressing the load change of the fossil fuel combustion thermal
power system can be realized.
Embodiment 4
[0125] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the fourth
embodiment of the present invention will be explained by referring
to FIGS. 8 and 9.
[0126] FIG. 8 shows the fossil fuel combustion thermal power system
including the carbon dioxide separation and capture unit of the
fourth embodiment of the present invention.
[0127] The fossil fuel combustion thermal power system 100
composing the fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the fourth
embodiment shown in FIG. 8 includes a fossil fuel combustion boiler
201 for burning fossil fuel, heating condensed water supplied from
the condenser, and generating steam at high temperature and high
pressure and a high-pressure turbine 203 for leading and driving
the steam generated by the boiler 201 through a main steam pipe 202
from the boiler 201.
[0128] The steam decompressed due to an occurrence of power by the
high-pressure turbine 203 for flowing down through an exhaust pipe
204 of the high-pressure turbine is supplied to the boiler 201 and
is heated again by the boiler 201 to reheat the steam.
[0129] The fossil fuel combustion thermal power system 100 includes
an intermediate-pressure turbine 206 for leading and driving the
reheat steam heated by the boiler 201 through a high-temperature
reheat steam pipe 205 from the boiler 201, a first low-pressure
turbine 208 for leading and driving the steam decompressed due to
an occurrence of power by the intermediate-pressure turbine 206
through a intermediate-pressure turbine exhaust pipe 207, and a
first condenser 209 for condensing the steam decompressed due to an
occurrence of power by the first low-pressure turbine 208.
[0130] The first condenser 209 includes a cooling water pipe 210
and exchanges heat between the steam led to the condenser 209 and
the cooling water flowing in the cooling water pipe, and thereby
condenses the steam. The steam turbine heat cycle is structured so
as to re-send the condensed water condensed by the condenser 209 to
the boiler 201, change it to steam, and send the steam to the
high-pressure turbine 203.
[0131] The high-pressure turbine 203, the intermediate-pressure
turbine 206, and the low-pressure turbine 208 are connected by a
turbine rotor 211. Further, to the turbine rotor 211, a generator
212 is connected and by the rotary power of the high-pressure
turbine 203, the intermediate-pressure turbine 206, and the
low-pressure turbine 208, the generator 212 is driven and the
output of the steam turbine is taken out as electric power.
[0132] In the fossil fuel combustion thermal power system 100, a
first extraction pipe 240 for extracting and leading a part of the
exhaust steam branching from the intermediate-pressure turbine
exhaust pipe 207 of the intermediate-pressure turbine 206 and
flowing down in the intermediate-pressure turbine exhaust pipe 207
and a PCC unit blast pipe 241 connected to the first extraction
pipe 240 for sending the extraction steam flowing down in the first
extraction pipe 240 to a reboiler 225 and a reclaimer 226 which are
installed in the carbon dioxide separation and capture unit 200
which will be described later are installed. In the PCC unit blast
pipe 241, a stop valve 250 is installed.
[0133] In the fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the fourth
embodiment shown in FIG. 8, the fossil fuel combustion thermal
power system 100 and the carbon dioxide separation and capture unit
200 (PCC unit) for separating and capturing the carbon dioxide
included in the exhaust gas of the boiler discharged from the
boiler 201 of the fossil fuel combustion thermal power system 100
by burning fossil fuel are installed.
[0134] In the carbon dioxide separation and capture unit 200 shown
in FIG. 8, the boiler exhaust gas including carbon dioxide which is
discharged from the boiler 201 and is branched and supplied from a
boiler exhaust gas system pipe 213 flows down through a boiler
exhaust gas pipe 214, is boosted by a boiler exhaust gas boost fan
215 installed in the boiler exhaust gas pipe 214, then is supplied
to and cooled by a boiler exhaust gas cooler 216, and is supplied
to an absorption tower 217 for absorbing carbon dioxide gas from
the boiler exhaust gas cooler 216 by the absorbing solution.
[0135] The carbon dioxide gas included in the boiler exhaust gas is
absorbed by the absorbing solution in the absorption tower 217 and
the processed gas which is boiler exhaust gas including no carbon
dioxide is supplied to a chimney 219 from the absorption tower 217
through an exit boiler exhaust gas pipe 218 of the absorption tower
and is discharged from the chimney 219 into the atmosphere.
[0136] Further, among the boiler exhaust gas including carbon
dioxide supplied from the boiler 201 through the boiler exhaust gas
system pipe 213, the boiler exhaust gas not supplied to the
absorption tower 217, by a valve opening operation of a bypass
butterfly valve 221 installed on a bypass gas pipe 220 for
bypassing the carbon dioxide separation and capture unit 200, is
directly led to the chimney 219 through the bypass gas pipe
220.
[0137] The enriched absorbing solution absorbing carbon dioxide gas
included in the boiler exhaust gas in the absorption tower 217 and
including much carbon dioxide is boosted by an enriched absorbing
solution transfer pump 223 installed in the supply path of the
absorbing solution for supplying the absorbing solution of the
absorption tower 217 to a reproduction tower 222, is supplied to an
absorbing solution heat exchanger 224 similarly installed in the
supply path of the absorbing solution, is heated by the absorbing
solution heat exchanger 224, and then is supplied to the
reproduction tower 222.
[0138] The enriched absorbing solution supplied from the absorption
tower 217 to the reproduction tower 222 is heated by supplying
vapor generated by the reboiler 225 and reclaimer 226 to the
reproduction tower 222 from the reboiler 225 and reclaimer 226 and
the carbon dioxide gas absorbed in the reproduction tower 222 is
separated.
[0139] By heating by the vapor supplied from the reboiler 225, the
carbon dioxide separated from the enriched absorbing solution in
the reproduction tower 222 is discharged from the reproduction
tower 222, is cooled by an exit gas cooler 227 installed on the
exit side of the reproduction tower 222, and then is supplied to a
reflux drum 228 for separating moisture, and the moisture included
in the carbon dioxide gas is separated. The carbon dioxide gas with
the moisture separated is supplied to and stored in a carbon
dioxide liquefying and storing facility (not drawn) from the reflux
drum 228 through a carbon dioxide gas exhaust pipe 229.
[0140] Further, the moisture separated by the reflux drum 228 is
structured so as to be boosted by a reflux drum pump 230 and be
returned to the reproduction tower 222.
[0141] And, a part of the absorbing solution in the reproduction
tower 222 is pulled out through an absorbing solution pull-out pipe
231 in the reproduction tower and is branched and supplied to the
reboiler 225 and reclaimer 226 and it is heated by the reboiler 225
supplied with the heating steam extracted from the steam turbine
cycle of the fossil fuel combustion thermal power system 100, that
is, the extraction steam extracted from the intermediate-pressure
turbine 206 as a heat source.
[0142] The reclaimer 226 is a cleaning unit of the absorbing
solution for heating the absorbing solution using the extraction
steam extracted from the intermediate-pressure turbine 206 as a
heat source, separating impurities included in the absorbing
solution, and discharging them out of the system.
[0143] The heating steam necessary to heat the reboiler 225 and
reclaimer 226 is obtained by extracting a part of the extraction
steam flowing down in the intermediate-pressure turbine 206
composing the fossil fuel combustion thermal power system 100 and
sending it to the reboiler 225 and reclaimer 226 through the first
extraction pipe 240 and the PCC unit blast pipe 241.
[0144] The absorbing solution separating carbon dioxide by heating
the absorbing solution in the reproduction tower 222 is boosted by
a lean absorbing solution transfer pump 232 installed in the return
path of the absorbing solution for returning the absorbing solution
from the reproduction tower 222 to the absorption tower 217, is
supplied to a lean absorbing solution cooler 233 similarly
installed in the return path of the absorbing solution, is cooled
by the lean absorbing solution cooler 233, and then is returned to
the absorption tower 217, thus the absorbing solution is circulated
between the absorption tower 217 and the reproduction tower
222.
[0145] And, the carbon dioxide separation and capture unit 200 is
structured so as to supply the extraction steam extracted from the
intermediate-pressure turbine 206 through the first extraction pipe
240 and the PCC unit blast pipe 241 to the reboiler 225 and
reclaimer 226 as a heat source, indirectly heat the absorbing
solution pulled out from the reproduction tower 222 through the
absorbing solution pull-out pipe 231 in the reproduction tower by
the reboiler 225, thereby generating normal steam at a desired
temperature and pressure, and supply the generated steam to the
reproduction tower 222 through a steam pipe 234 at the reboiler
exit.
[0146] The PCC unit blast pipe 241 on the upstream side of the
reboiler 225 and reclaimer 226 branches to a reboiler-side pipe 235
and a reclaimer-side pipe 236, and the reboiler-side pipe 235 is
connected to the reboiler 225, and the reclaimer-side pipe 236 is
connected to the reclaimer 226. Further, on the reboiler-side pipe
234, a flow rate control valve 237 is installed, and on the
reclaimer-side pipe 235, a flow rate control valve 238 is
installed, and so the steam generated by the reboiler 225 is
controlled to a desired temperature and pressure, and the flow rate
of the extraction steam from the intermediate-pressure turbine 206
supplied to the reboiler 225 is adjusted.
[0147] In the fossil fuel combustion thermal power system 100,
furthermore, a second low-pressure turbine blast pipe 246 branching
from the first extraction pipe 240, a second low-pressure turbine
242 installed independently of the main steam turbine unit
connected with the turbine rotor 211 to be driven by the extraction
steam from the intermediate-pressure turbine 206 introduced through
the second low-pressure turbine blast pipe 246, and a second
condenser 245 for introducing the steam boosted by driving the
second low-pressure turbine 242, exchanging heat between the
introduced steam and the cooling water flowing in the cooling pipe
10, thereby cooling and condensing the steam are installed. The
condensed water condensed by the second condenser 245 is sent again
to the boiler 201.
[0148] On the entrance side of the second low-pressure turbine 242,
a low-pressure turbine entrance control valve 243 for controlling
the flowing steam quantity of the second low-pressure turbine 242
and the output of the second low-pressure turbine 242 is installed.
Further, to the second low-pressure turbine 242, a generator 244 is
connected and it is structured so as to take out the power of the
second low-pressure turbine 242 as electric power.
[0149] Further, the fossil fuel combustion thermal power system 100
includes a condenser blast pipe 248 for leading the steam branching
from the first extraction pipe 240 on the upstream side of the
second low-pressure turbine blast pipe 246 and flowing down in the
first extraction pipe 240 to the first condenser 209.
[0150] On the intermediate-pressure turbine exhaust pipe 207, an
intermediate-pressure turbine exhaust pressure regulating valve 251
for adjusting the exhaust steam pressure of the
intermediate-pressure turbine is installed.
[0151] On the second low-pressure turbine blast pipe 246, a
switching valve 247 is installed and on the condenser blast pipe
248, a switching valve 249 is installed.
[0152] FIG. 9 is a partial diagram showing the portion of the
fossil fuel combustion thermal power system 100 of the fossil fuel
combustion thermal power system including the carbon dioxide
separation and capture unit of the fourth embodiment shown in FIG.
8.
[0153] In the fossil fuel combustion thermal power system 100 shown
in FIG. 9, an intermediate-pressure turbine exhaust pressure
detector 252 installed on the intermediate-pressure turbine exhaust
pipe 207 for detecting the intermediate-pressure turbine exhaust
pressure and a blast pressure detector 253 installed on the PCC
unit blast pipe 241 for detecting the blast pressure are
installed.
[0154] Further, a control unit 600 is installed and by the control
unit 600, the operation of the second low-pressure turbine 242 is
controlled. Namely, by an instruction signal of the control unit
600, the opening angle of the low-pressure turbine entrance control
valve 243 is adjusted and the flow rate of the steam supplied to
the second low-pressure turbine 242 is controlled.
[0155] On the other hand, when the main unit of the carbon dioxide
separation and capture unit 200 trips from some cause, for example,
when the enriched absorbing solution transfer pump 223 or the lean
absorbing solution transfer pump 231 for transferring the absorbing
solution trips and the operation of the carbon dioxide separation
and capture unit 200 stops urgently, the steam supply from the
fossil fuel combustion thermal power system 100 to the carbon
dioxide separation and capture unit 200 may be required to stop
immediately.
[0156] When the steam supply to the carbon dioxide separation and
capture unit 200 stops immediately, the surplus steam flows into
the first low-pressure turbine 208 of the steam turbine via the
intermediate-pressure turbine exhaust pipe 207 and the
intermediate-pressure turbine exhaust pressure regulating valve
251, and the steam quantity flowing in the first low-pressure
turbine 208 suddenly increases and suddenly exceeds the allowable
flow-in steam quantity from the viewpoint of the intensity of the
turbine rotor blade of the first low-pressure turbine 208, thus
there is the possibility that a load beyond the allowable range may
be applied to the low-pressure turbine rotor blade. As a means for
avoiding such a sudden load change of the low-pressure turbine
caused by the urgent stop of the carbon dioxide separation and
capture unit 200, the present invention installs a second
low-pressure turbine 242 as an urgent shift destination of the
surplus steam.
[0157] The control unit 600 installed in the fossil fuel combustion
thermal power system 100 shown in FIG. 9 controls the operation of
the second low-pressure turbine 242 and when the carbon dioxide
separation and capture unit 200 stop urgently the operation of
sequentially switching the supply destination of the extraction
steam flowing in the first extraction pipe 240 from the carbon
dioxide separation and capture unit 200 to the first condenser 209
and second low-pressure turbine 242.
[0158] When the carbon dioxide separation and capture unit 200
stops urgently, for example, when the enriched absorbing solution
transfer pump 223 or the lean absorbing solution transfer pump 232
which are main units of the carbon dioxide separation and capture
unit 200 trips, and the operation of the carbon dioxide separation
and capture unit 200 stops urgently, and the steam supplied from
the steam turbine cycle of the fossil fuel combustion thermal power
system 100 to the reboiler 225 is required to stop immediately,
from the sensors respectively installed in the enriched absorbing
solution transfer pump 223 and the lean absorbing solution transfer
pump 232, a trip signal 223a of the enriched absorbing solution
transfer pump 223 or a trip signal 232a of the lean absorbing
solution transfer pump 232 is sent to the control unit 600.
[0159] Further, as a means for detecting the other faults in the
carbon dioxide separation and capture unit 200, by the blast
pressure detector 253, the change of the pressure of the steam
flowing down in the PCC unit blast pipe 241 is detected and when
the detector 253 detects an abnormal change of the pressure, a trip
signal is sent from the detector 253 to the control unit 600.
[0160] If the control unit 600 detects input of the trip signal, by
an instruction signal from the control unit 600, the stop valve 250
is automatically completely closed and the flow of the extraction
steam to the carbon dioxide separation and capture unit 200 is
interrupted. Further, the switching valve 249 is opened by the
instruction signal from the control unit 600, and the supply
destination of the extraction steam is switched from the carbon
dioxide separation and capture unit 200 to the first condenser 209,
and the surplus extraction steam is permitted once to flow into the
first condenser 209 through the condenser blast pipe 248 and is
captured. Thereafter, by the instruction signal of the control unit
600, the switching valve 249 is closed gradually, thus the opening
angles of the second switching valve 247 and the second
low-pressure turbine entrance control valve 243 are adjusted, and
the supply destination of the extraction steam is controlled so as
to be gradually switched to the second low-pressure turbine 242.
Further, when switching the supply destination of the extraction
steam from the carbon dioxide separation and capture unit 200 to
the first condenser 209 and second low-pressure turbine 242, the
control unit 600, on the basis of a signal of the
intermediate-pressure turbine exhaust pressure detector 252 for
detecting the pressure change of the intermediate-pressure turbine
exhaust steam, so as to prevent the intermediate-pressure turbine
exhaust steam from an excessive reduction in pressure exceeding a
predetermined set value by switching the flow path, controls the
opening angles of the switching valve 249, switching valve 247, and
second low-pressure turbine entrance control valve 243. When the
intermediate-pressure turbine exhaust steam is excessively
extracted by switching of the supply path, the
intermediate-pressure turbine exhaust steam is excessively reduced
in pressure and there is the possibility that a load exceeding the
allowable quantity may be applied to the last stage blade of the
intermediate-pressure turbine. By use of this constitution, by
avoiding the load on the last stage blade of the
intermediate-pressure turbine, the flow path switching control can
be executed.
[0161] The surplus steam flowing into the second low-pressure
turbine 242 from the intermediate-pressure turbine 206 by switching
the flow path drives the second low-pressure turbine 242 and the
generator 244, thus electric power is obtained. The steam
discharged by driving the second low-pressure turbine 242 is
captured and condensed by the condenser 245 and the condensed water
is sent to the boiler 201.
[0162] The steam quantity required by the reboiler 225 is far
larger than the steam quantity required by the reclaimer 226 and is
equivalent to about 15% to 20% of the total quantity of evaporation
of the boiler. Therefore, when the carbon dioxide separation and
capture unit 200 stops urgently, even though a large quantity of
surplus steam is generated, the control unit 600 performs the
control operation aforementioned, and thus the surplus steam urgent
relief function can be fulfilled effectively. Therefore, the sudden
flow-in exceeding the allowable quantity on the side of the
low-pressure turbine (first low-pressure turbine) of the steam
turbine unit can be avoided, and the load change of the boiler 201
and steam turbine due to the surplus steam can be suppressed, so
that even at the time of an urgent stop of the carbon dioxide
separation and capture unit 200, the stable operation of the fossil
fuel combustion thermal power system 100 can be continued.
[0163] Further, even during stopping of the carbon dioxide
separation and capture unit 200, a large quantity of surplus steam
is sent to the second low-pressure turbine 242 without being thrown
away and can be captured as electric power, thus more electrical
energy can be generated.
Embodiment 5
[0164] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the fifth
embodiment of the present invention will be explained by referring
to FIGS. 10 and 11.
[0165] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the fifth
embodiment which is this embodiment is common in the basic
constitution to the fossil fuel combustion thermal power system
including the carbon dioxide separation and capture unit of the
fourth embodiment explained previously. Therefore, the explanation
of the constitution common to the two is omitted and only the
different portions will be explained below.
[0166] The fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit of the fifth
embodiment shown in FIG. 10 includes the fossil fuel combustion
thermal power system 100 composing the steam turbine unit and the
carbon dioxide separation and capture unit 200 for separating and
capturing carbon dioxide from the boiler exhaust gas.
[0167] In this embodiment, in the fossil fuel combustion thermal
power system 100, a second extraction pipe 254 branching from the
high-pressure turbine exhaust pipe 204 of the high-pressure turbine
203 for permitting a part of the steam flowing down in the
high-pressure turbine exhaust pipe 204 to flow down, a
back-pressure turbine blast pipe 255 connected to the first
extraction pipe 240 through which a part of the steam flowing down
in the intermediate-pressure turbine exhaust pipe 207 flows down, a
back-pressure turbine 256 driven by the extraction steam led
through the second extraction pipe 254 and the back-pressure
turbine blast pipe 255, and a generator 265 for generating power by
the power of the back-pressure turbine 256 are installed.
[0168] On the entrance side of the back-pressure turbine 256, a
first back-pressure turbine entrance control valve 259 for
controlling the flow-in steam quantity from the side of the second
extraction pipe 254 to the back-pressure turbine 256 and a second
back-pressure turbine entrance control valve 260 for controlling
the flow-in steam quantity from the side of the back-pressure
turbine blast pipe 255 to the back-pressure turbine 256 are
installed. Further, on the exit side of the back-pressure turbine
256, a back-pressure turbine exhaust pipe path 261 permitting the
back-pressure turbine exhaust steam decompressed by driving the
back-pressure turbine 256 to flow down, a stop valve 262 installed
in the back-pressure turbine exhaust pipe path 261, and the PCC
unit blast pipe 241 connected to the back-pressure turbine exhaust
pipe path 261 for sending the back-pressure turbine exhaust steam
to the reboiler 225 and reclaimer 226 which are installed in the
carbon dioxide separation and capture unit 200 which will be
described later are installed.
[0169] To the second extraction pipe 254, a second low-pressure
turbine entrance pipe 263 including the stop valve 264 is
connected. The second low-pressure turbine entrance pipe 263 is
connected to the second low-pressure turbine 242 and is structured
so as to lead the steam flowing down in the second low-pressure
turbine entrance pipe 263 to the second low-pressure turbine
242.
[0170] Further, a second condenser blast pipe 266 branching from
the second low-pressure turbine entrance pipe 263 and
interconnecting to the first condenser 209 is installed and in the
second condenser blast pipe 266, a switching valve 267 is
installed.
[0171] Further, the fossil fuel combustion thermal power system 100
includes a third extraction pipe 270 branching from the first
extraction pipe 240 and interconnecting to the second low-pressure
turbine entrance pipe 263 for leading the extraction steam flowing
down in the first extraction pipe 240 to the second low-pressure
turbine 242. In the third extraction pipe 270, a switching valve
271 for controlling switching of the flow path of the extraction
steam to the side of the second low-pressure turbine is
installed.
[0172] Furthermore, the first extraction pipe 240 includes a first
back-pressure turbine bypass pipe 272 branching on the downstream
side of the condenser blast pipe 248 and the third extraction pipe
270, connecting to the PCC unit blast pipe 241 for permitting the
extraction steam flowing down in the first extraction pipe 240 to
bypass the back-pressure turbine 256 and leading it to the PCC unit
blast pipe 241. The back-pressure turbine bypass pipe 272 includes
a switching valve 273.
[0173] Further, the high-pressure turbine exhaust pipe 204 includes
a second back-pressure turbine bypass pipe 274 branching on the
downstream side of the second extraction pipe 254, connecting to
the first back-pressure turbine bypass pipe 272, permitting the
extraction steam of the high-pressure turbine to bypass the
back-pressure turbine 256, and leading it to the reboiler 225 and
reclaimer 226 of the carbon dioxide separation and capture unit 200
through the PCC unit blast pipe 241. The second back-pressure
turbine bypass pipe 274 includes a switching valve 268 for
controlling the extraction steam quantity bypassing the
back-pressure turbine 256.
[0174] FIG. 11 is a partial diagram showing the portion of the
fossil fuel combustion thermal power system 100 of the fossil fuel
combustion thermal power system including the carbon dioxide
separation and capture unit of the fifth embodiment shown in FIG.
10.
[0175] In the fossil fuel combustion thermal power system 100, a
control unit 700 is installed and by the control unit 700, the
operations of the second low-pressure turbine 242 and back-pressure
turbine 256 are controlled.
[0176] In the fossil fuel combustion thermal power system 100
relating to the fifth embodiment, during the rated load operation
of the steam turbine, a system of extracting steam from the
intermediate-pressure turbine exhaust pipe 207 and supplying the
intermediate-pressure turbine exhaust steam to the back-pressure
turbine 256 through the first extraction pipe 240, back-pressure
turbine blast pipe 255, and second back-pressure turbine entrance
control valve 260 is adopted. On the other hand, when the steam
turbine is transferred from the rated load operation to the partial
load operation, the steam pressure of the exhaust gas of the
intermediate-pressure turbine 206 is lowered, and the exhaust steam
cannot be sufficiently pumped to the back-pressure turbine 256, so
that in place of the system of extracting steam from the
intermediate-pressure turbine exhaust pipe 207 and supplying the
intermediate-pressure turbine exhaust steam to the back-pressure
turbine 256 through the first extraction pipe 240, back-pressure
turbine blast pipe 255, and second back-pressure turbine entrance
control valve 260, the system is switched to a system of supplying
a part of the high-pressure steam flowing down in the high-pressure
turbine exhaust pipe 204 from the high-pressure turbine 203 to the
back-pressure turbine 256 through the second extraction pipe 254
and first back-pressure turbine entrance control valve 259, and the
steam pressure necessary to drive the back-pressure turbine 256 is
ensured.
[0177] In the fossil fuel combustion thermal power system 100, when
the steam turbine is in the partial load operation, the control
unit 700 sends an instruction signal, opens the switching valve 257
installed in the second extraction pipe 254, leads the extraction
steam of the high-pressure turbine 203 to the back-pressure turbine
256, adjusts the opening angle of the first back-pressure turbine
entrance control valve 259, thereby controlling the flow rate, and
drives and controls the back-pressure turbine 256 by the extraction
steam from the high-pressure turbine 203.
[0178] Next, the steam turbine transfers from the partial load
operation to the rated load operation, and the steam pressure
flowing in the intermediate-pressure turbine exhaust pipe 207 is
increased to a sufficient pressure to be pumped to the
back-pressure turbine 256, and then the control unit 700 transmits
the instruction signal, thus the switching valve 254 and first
back-pressure turbine entrance control valve 259 are closed, and
the switching valve 258 is opened, and the extraction steam of the
intermediate-pressure turbine 206 is led to the back-pressure
turbine 256, and the opening angle of the second back-pressure
turbine entrance control valve 260 is adjusted, thus the flow rate
is controlled, and by the steam extracted from the
intermediate-pressure turbine exhaust steam, the back-pressure
turbine 256 is driven and controlled. The back-pressure turbine
exhaust steam after the back-pressure turbine 256 is driven is sent
to the reboiler 225 and reclaimer 226 of the carbon dioxide
separation and capture unit 200 through the back-pressure turbine
exhaust pipe path 261 and the PCC unit blast pipe 241.
[0179] On the other hand, during the partial load operation of the
steam turbine, when the back-pressure turbine 256 trips from some
cause, for example, when an abnormal value of a generator output
signal of the back-pressure turbine 256 is input to the control
unit 700, the control unit 700 transmits an instruction signal and
the switching valve 257 and the first back-pressure turbine
entrance control valve 259 are closed. Further, the switching valve
268 is opened and the extraction steam is led to the PCC unit blast
pipe 241 through the second back-pressure turbine bypass pipe 274
and first back-pressure turbine bypass pipe 272.
[0180] Further, during the partial load operation of the steam
turbine, when the carbon dioxide separation and capture unit 200
trips, for example, when the enriched absorbing solution transfer
pump 223 or the lean absorbing solution transfer pump 232 which are
main units of the carbon dioxide separation and capture unit 200
trips, and the operation of the carbon dioxide separation and
capture unit 200 stops urgently, and the steam supplied from the
steam turbine cycle of the fossil fuel combustion thermal power
system 100 to the reboiler 225 is required to stop immediately, a
trip signal 223a of the enriched absorbing solution transfer pump
223 or a trip signal 232a of the lean absorbing solution transfer
pump 232 which are input from the sensors respectively installed in
the enriched absorbing solution transfer pump 223 and the lean
absorbing solution transfer pump 232 is sent to the control unit
700.
[0181] Further, as a means for detecting the other faults in the
carbon dioxide separation and capture unit 200, by a first blast
pressure detector 275 installed on the back-pressure turbine blast
pipe 255, the change of the pressure of the steam flowing down in
the PCC unit blast pipe 241 is detected and when the detector 275
detects an abnormal change of the pressure, a trip signal is sent
from the detector 275 to the control unit 700.
[0182] When the back-pressure turbine 256 is stopped and the bypass
system is used, the back-pressure turbine blast pipe 255 is not
used and the first blast pressure detector 275 cannot be used.
Therefore, when a second blast pressure detector 276 installed on
the downstream side of the joining point of the PCC unit blast pipe
241 to the first back-pressure turbine bypass pipe 272 detects the
pressure change of the supplied gas, and the detector 276 detects
the abnormal change of the pressure, a trip signal is sent from the
detector 276 to the control unit 700.
[0183] If the control unit 700 receives the input of the trip
signal, by an instruction signal from the control unit 700, the
switching valves 257 and 268 are closed, and the switching valve
267 is opened simultaneously, and the extraction steam is led to
and captured by the first condenser 209 through the second
low-pressure turbine entrance pipe 263 and second condenser blast
pipe 266. Thereafter, by the instruction signal from the control
unit 700, the switching valve 267 is closed gradually, thus the
opening angles of the stop valve 264 and the entrance control valve
243 of the second low-pressure turbine 242 are adjusted, and the
supply destination of the extraction steam is controlled so as to
be gradually switched to the second low-pressure turbine 242.
[0184] On the other hand, during the rated load operation of the
steam turbine, when the back-pressure turbine 256 trips from some
cause, the control unit 700 transmits an instruction signal, closes
the switching valve 258, opens the switching valve 273, and leads
the extraction steam to the PCC unit blast pipe 241 through the
first back-pressure turbine bypass pipe 272.
[0185] Further, when the carbon dioxide separation and capture unit
trips, a trip signal is input to the control unit 700 from the
enriched absorbing solution transfer pump 223, lean absorbing
solution transfer pump 232, and detectors 275 and 276.
[0186] If the control unit 700 receives the trip signal of the
carbon dioxide separation and capture unit 200, by an instruction
signal from the control unit 700, the switching valves 258 and 273
are closed, and the switching valve 249 is opened, and the surplus
steam is captured once by the first condenser 209. Thereafter, by
the instruction signal from the control unit 700, the switching
valve 249 is closed gradually, thus the opening angles of the
switching valve 271 and the entrance control valve 243 of the
second low-pressure turbine 242 are adjusted, and the supply
destination of the extraction steam is controlled so as to be
gradually switched to the second low-pressure turbine 242. Further,
when switching the flow path of the extraction steam to the first
condenser 209 and second low-pressure turbine 242 through the third
extraction pipe 270 and condenser blast pipe 248, the control unit
700, on the basis of a signal of the intermediate-pressure turbine
exhaust pressure detector 252 for detecting the pressure change of
the intermediate-pressure turbine exhaust steam, to prevent the
intermediate-pressure turbine exhaust steam from excessively
reducing in pressure beyond a predetermined set value due to
switching of the flow path, controls the opening angles of the
switching valve 249, the switching valve 271, and the entrance
control valve 243 of the second low-pressure turbine 242. When the
intermediate-pressure turbine exhaust steam is extracted
excessively by switching of the supply path, the
intermediate-pressure turbine exhaust steam is excessively reduced
in pressure and there is the possibility that a load exceeding the
allowable quantity may be applied to the last stage blade of the
intermediate-pressure turbine. By use of this constitution, by
avoiding the load on the last stage blade of the
intermediate-pressure turbine, the flow path switching control can
be executed.
[0187] In the fossil fuel combustion thermal power system including
the carbon dioxide separation and capture unit having the
aforementioned constitution, during the rated load operation, the
exhaust gas of the intermediate-pressure turbine 206 can be
supplied to the back-pressure turbine 256 to generate electric
power and during the partial load operation, the exhaust gas of the
high-pressure turbine 203 can be supplied to the back-pressure
turbine 256 to generate electric power.
[0188] Further, under the control aforementioned, even when the
back-pressure turbine 256 trips from some cause in the partial load
operation and the rated load operation, the operation of the
back-pressure turbine 256 is stopped, thus the extraction steam is
permitted to bypass the back-pressure turbine 256, and thereby can
be supplied to the side of the carbon dioxide separation and
capture unit 200, and the carbon dioxide separation and capture
unit can 200 be operated continuously.
[0189] Furthermore, even when the carbon dioxide separation and
capture unit 200 stops, the surplus steam can be shifted to the
second low-pressure turbine 242, and a sudden flow-in of steam
exceeding the allowable quantity on the side of the low-pressure
turbine (the first low-pressure turbine 208) of the steam turbine
can be avoided, and the load change of the boiler 201 and steam
turbine due to the surplus steam is suppressed, so that the stable
operation of the fossil fuel combustion thermal power system 100
can be continued.
[0190] Further, even during stopping of the carbon dioxide
separation and capture unit 200 and the back-pressure turbine 256,
a large quantity of surplus steam is sent to the second
low-pressure turbine 242 without being throwing away and can be
captured as electric power, thus more electrical energy can be
generated.
[0191] The present invention can be applied to the fossil fuel
combustion thermal power system including the carbon dioxide
separation and capture unit.
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