U.S. patent application number 09/753558 was filed with the patent office on 2001-05-17 for coal gasification combined cycle power generation plant and an operating method thereof.
This patent application is currently assigned to KABUSHIKI KAISHA TOSHIBA. Invention is credited to Iwai, Yasunori, Onoda, Akihiro.
Application Number | 20010001171 09/753558 |
Document ID | / |
Family ID | 16847840 |
Filed Date | 2001-05-17 |
United States Patent
Application |
20010001171 |
Kind Code |
A1 |
Onoda, Akihiro ; et
al. |
May 17, 2001 |
Coal gasification combined cycle power generation plant and an
operating method thereof
Abstract
A coal gasification combined cycle power generation plant
generally includes a gas turbine system, a fuel supply system, an
air supply system and an exhaust gas system, which are operatively
connected to each other. The gas turbine system includes a
combustor for selectively burning a coal gasification fuel obtained
by gasifying a coal and a liquid fuel atomized by an atomization
air and a gas turbine to which a combustion gas generated in the
combustor is supplied. The fuel supply system is provided with a
liquid fuel supply passage for the combustor through a fuel nozzle
provided for the combustor, an atomization air supply passage for
the combustor through the fuel nozzle and a coal gasification fuel
supply passage for the combustor through the fuel nozzle, all of
these supply passages being arranged so as to be adjacent to each
other. The atomization air supply passage is provided with an
outlet portion to which a branching outlet port for injecting the
atomization air toward an outlet portion of the coal gasification
supply passage is formed so as to secure a minimum flow rate for
preventing the coal gasification fuel from conversely flowing into
the fuel nozzle.
Inventors: |
Onoda, Akihiro;
(Kawasaki-Shi, JP) ; Iwai, Yasunori;
(Yokohama-Shi, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Assignee: |
KABUSHIKI KAISHA TOSHIBA
72 Horikawa-Cho, Saiwai-Ku, Kawasaki-Shi, Kanagawa -Ken
Kawasaki-Shi
JP
|
Family ID: |
16847840 |
Appl. No.: |
09/753558 |
Filed: |
January 4, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09753558 |
Jan 4, 2001 |
|
|
|
09138674 |
Aug 24, 1998 |
|
|
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Current U.S.
Class: |
60/776 ;
60/39.12; 60/39.463 |
Current CPC
Class: |
F02C 3/28 20130101; F23R
2900/00002 20130101; Y02E 20/16 20130101; F23D 17/002 20130101;
Y02E 20/18 20130101; F23R 3/36 20130101 |
Class at
Publication: |
60/39.06 ;
60/39.12; 60/39.463 |
International
Class: |
F02C 003/28 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 22, 1997 |
JP |
P.9-226606 |
Claims
1. A coal gasification combined cycle power generation plant
including a gas turbine system, a fuel supply system, an air supply
system and an exhaust gas system, which are operatively connected
to each other, said gas turbine system including a combustor
provided with means for selectively burning a coal gasification
fuel obtained by gasifying a coal and a liquid fuel atomized by an
atomization air and a gas turbine to which a combustion gas
generated in the combustor is supplied, said combustor being
provided with a fuel nozzle, a liner disposed inside the combustor
and a combustion air passage formed between the liner and an outer
casing of the combustor, said fuel supply system being provided
with a liquid fuel supply passage for the combustor through the
fuel nozzle, an atomization air supply passage for the combustor
through the fuel nozzle and a coal gasification fuel supply passage
for the combustor through the fuel nozzle, all of said supply
passages being arranged so as to be adjacent to each other, said
atomization air supply passage being provided with an outlet
portion to which a branching outlet port for injecting the
atomization air toward an outlet portion of the coal gasification
supply passage is formed.
2. A coal gasification combined cycle power generation plant
including a gas turbine system, a fuel supply system, an air supply
system and an exhaust gas system, which are operatively connected
to each other, said gas turbine system including a combustor
provided with means for selectively burning a coal gasification
fuel obtained by gasifying a coal and a liquid fuel atomized by an
atomization air and a gas turbine to which a combustion gas
generated in the combustor is supplied, said combustor being
provided with a fuel nozzle, a liner disposed inside the combustor
and a combustion air passage formed between the liner and an outer
casing of the combustor, said fuel supply system being provided
with a liquid fuel supply passage for the combustor through the
fuel nozzle, an atomization air supply passage for the combustor
through the fuel nozzle and a coal gasification fuel supply passage
for the combustor through the fuel nozzle, all of said supply
passages being arranged so as to be adjacent to each other, said
atomization air supply passage being provided with a passage wall
portion and an outlet portion and a blowout hole for blowing out
the atomization air to the coal gasification fuel supply passage in
a vicinity of the outlet portion.
3. A coal gasification combined cycle power generation plant
including a gas turbine system, a fuel supply system, an air supply
system and an exhaust gas system, which are operatively connected
to each other, said gas turbine system including a combustor
provided with means for selectively burning a coal gasification
fuel obtained by gasifying a coal and a liquid fuel atomized by an
atomization air and a gas turbine to which a combustion gas
generated in the combustor is supplied, said combustor being
provided with a fuel nozzle, a liner disposed inside the combustor
and a combustion air passage formed between the liner and an outer
casing of the combustor, said fuel supply system being provided
with a liquid fuel supply passage for the combustor through the
fuel nozzle, an atomization air supply passage for the combustor
through the fuel nozzle and a coal gasification fuel supply passage
for the combustor through the fuel nozzle, all of said supply
passages being arranged so as to be adjacent to each other, said
combustion air passage being provided with an outlet portion
through which a combustion air from a compressor of the gas turbine
system is blown toward the liner of the combustor and said outlet
portion is provided with a combustion air injecting portion so as
to inject a combustion air toward an outlet portion of the coal
gasification fuel supply passage.
4. A coal gasification combined cycle power generation plant
including a gas turbine system, a fuel supply system, an air supply
system and an exhaust gas system, which are operatively connected
to each other, said gas turbine system including a combustor
provided with means for selectively burning a coal gasification
fuel obtained by gasifying a coal and a liquid fuel atomized by an
atomization air and a gas turbine to which a combustion gas
generated in the combustor is supplied, said combustor being
provided with a fuel nozzle, a liner disposed inside the combustor
and a combustion air passage formed between the liner and an outer
casing of the combustor, said fuel supply system being provided
with a liquid fuel supply passage for the combustor through the
fuel nozzle, an atomization air supply passage for the combustor
through the fuel nozzle and a coal gasification fuel supply passage
for the combustor through the fuel nozzle, all of said supply
passages being arranged so as to be adjacent to each other, said
combustion air passage being communicated with said coal
gasification fuel supply passage so as to supply a combustion air
to the coal gasification fuel supply passage from the combustion
air passage and a control means for controlling an air flow rate in
the coal gasification fuel supply passage is provided for the
combustion air passage.
5. A coal gasification combined cycle power generation plant
according to any one of claims 1 to 4, further comprising a control
unit provided for the coal gasification fuel supply passage for
controlling a flow rate in a coal gasification operation.
6. A coal gasification combined cycle power plant according to
claim 5, wherein said control unit includes a normal operation flow
control means for controlling a flow rate in a coal gasification
fuel operation and an auxiliary flow control means for controlling
a flow rate of a little amount of the coal gasification fuel
supplied in a use of the liquid fuel.
7. A coal gasification combined cycle power generation plant
according to claim 6, further comprising a temperature detector
provided for the fuel nozzle for injecting the coal gasification
fuel to the combustor and a further control means for controlling
the auxiliary flow control means which operates in a case where the
temperature detector detects a temperature more than a fixed
temperature, and the further control means is set so as to secure a
minimum flow rate for preventing the coal gasification fuel from
conversely flowing into the fuel nozzle.
8. A method of operating a coal gasification combined cycle power
generation plant including a gas turbine system, a fuel supply
system, an air supply system and an exhaust gas system, which are
operatively connected to each other, said gas turbine system
including a combustor provided with means for selectively burning a
coal gasification fuel obtained by gasifying a coal and a liquid
fuel atomized by an atomization air and a gas turbine to which a
combustion gas generated in the combustor is supplied, said
combustor being provided with a fuel nozzle, a liner disposed
inside the combustor and a combustion air passage formed between
the liner and an outer casing of the combustor, said fuel supply
system being provided with a liquid fuel supply passage for the
combustor through the fuel nozzle, an atomization air supply
passage for the combustor through the fuel nozzle and a coal
gasification fuel supply passage for the combustor through the fuel
nozzle, all of said supply passages being arranged so as to be
adjacent to each other, said method comprising the steps of:
carrying out an operation by the combustion of the liquid fuel
during a start-up of the gas turbine; carrying out an operation by
the combustion of the coal gasification fuel after a predetermined
time elapsed thereafter; and supplying an incomplete coal
gasification fuel from the coal gasification fuel supply passage to
the combustor through the fuel nozzle until a coal gasification
fuel operation from the start-up of the gas turbine.
9. A method of operating a coal gasification combined cycle power
generation plant including a gas turbine system, a fuel supply
system, an air supply system and an exhaust gas system, which are
operatively connected to each other, said gas turbine system
including a combustor provided with means for selectively burning a
coal gasification fuel obtained by gasifying a coal and a liquid
fuel atomized by an atomization air and a gas turbine to which a
combustion gas generated in the combustor is supplied, said
combustor being provided with a fuel nozzle, a liner disposed
inside the combustor and a combustion air passage formed between
the liner and an outer casing of the combustor, said fuel supply
system being provided with a liquid fuel supply passage for the
combustor through the fuel nozzle, an atomization air supply
passage for the combustor through the fuel nozzle and a coal
gasification fuel supply passage for the combustor through the fuel
nozzle, all of said supply passages being arranged so as to be
adjacent to each other, said method comprising the steps of:
carrying out an operation by the combustion of the liquid fuel
during a start-up of the gas turbine; carrying out an operation by
the combustion of the coal gasification fuel after a predetermined
time elapsed thereafter; changing over the coal gasification fuel
operation into an operation by the combustion of the liquid fuel in
a case where a gas turbine load becomes less than a fixed load; and
supplying the coal gasification fuel of a fixed amount from the
coal gasification fuel supply passage to the combustor through the
fuel nozzle after a change-over is made from a combustion operation
by the coal gasification fuel to a combustion operation by the
liquid fuel.
10. A method of operating a coal gasification combined cycle power
generation plant including a gas turbine system, a fuel supply
system, an air supply system and an exhaust gas system, which are
operatively connected to each other, said gas turbine system
including a combustor provided with means for selectively burning a
coal gasification fuel obtained by gasifying a coal and a liquid
fuel atomized by an atomization air and a gas turbine to which a
combustion gas generated in the combustor is supplied, said
combustor being provided with a fuel nozzle, a liner disposed
inside the combustor and a combustion air passage formed between
the liner and an outer casing of the combustor, said fuel supply
system being provided with a liquid fuel supply passage for the
combustor through the fuel nozzle, an atomization air supply
passage for the combustor through the fuel nozzle and a coal
gasification fuel supply passage for the combustor through the fuel
nozzle, all of said supply passages being arranged so as to be
adjacent to each other, said method comprising the steps of:
carrying out an operation by the combustion of the liquid fuel
during a start-up of the gas turbine; carrying out an operation by
the combustion of the coal gasification fuel after a predetermined
time elapsed thereafter; changing over the coal gasification fuel
operation into an operation by the combustion of the liquid fuel at
the same time with a load dump in a case of a load dump; and
supplying the coal gasification fuel of a fixed amount from the
coal gasification fuel passage to the combustor through the a fuel
nozzle after a change-over is made from a combustion operation by
the coal gasification fuel to a combustion operation by the liquid
fuel.
11. An operating method according to any one of claims 8 to 10,
further comprising the step of controlling a flow rate in a coal
gasification operation.
12. An operating method according to claim 11, wherein said
controlling step further includes a normally controlling a flow
rate in a coal gasification fuel operation and auxiliarily
controlling a flow rate of a little amount of the coal gasification
fuel supplied in a use of the liquid fuel.
13. An operating method according to claim 12, wherein said
auxiliary flow control is controlled, in a case where a temperature
more than a fixed temperature is detected, so as to secure a
minimum flow rate for preventing the coal gasification fuel from
conversely flowing into the fuel nozzle.
Description
BACKGROUND OF THE INVENTION
1. The present invention relates to a coal gasification combined
cycle power generation plant or facility which selectively burns a
coal gasification fuel and a liquid fuel so as to generate a power
and also relates to a method of operating the same, particularly
for suitably preventing a combustion gas from conversely flowing
into a fuel passage of a coal gasification fuel when using a liquid
fuel and for improving a safety in a combustor section.
2. In recent years, in a viewpoint of an effective utilization of
natural resources, there has been made a study and development of a
coal gasification power generation equipment which uses a coal
gasification fuel as a heat source in a gas turbine power
generation plant, a combined cycle power generation plant or the
like.
3. In the coal gasification power generation equipment, a coal
gasification fuel is generated from coal by a coal gasification
furnace with the use of an air compressed by a gas turbine
compressor or oxygen generated by leading the air to an air
separator. The coal gasification fuel thus generated is supplied to
a gas turbine combustor so as to be burned, and then, by the
generated combustion gas, a gas turbine is driven to generate a
power.
4. However, the coal gasification fuel has a worse combustibility
as compared with a liquid fuel or a natural gas fuel and has a
small calorific value. Further, in the case where a combustion gas
temperature in the combustor becomes low, a lot of carbon monoxide
is discharged, thus providing a problem in operational
characteristics during a low load operation. Therefore, it is
desirable to employ a combined cycle facility for compensating the
defect of coal gasification fuel by burning other fuels during a
starting operation or a low load operation. In such viewpoint, a
liquid fuel has been employed as other fuel used in the combined
cycle plant.
5. As described above, the coal gasification combined cycle
equipment includes a combustor which can selectively burn a coal
gasification fuel gasified coal and a liquid fuel atomized by an
atomization air and is constructed in a manner that a combustion
gas generated by the combustor is supplied to a gas turbine so that
a generator is driven by a power of the gas turbine.
6. For example, first, the liquid fuel is supplied to the combustor
to be burned, and thereby, the gas turbine starts up. When the gas
turbine starts up a generation of coal gasification fuel is
simultaneously started in a coal gasification furnace. In an
operation of the coal gasification furnace during the start-up, an
compressed air from an auxiliary compressor or oxygen separated
from the compressed air by an air separator is used. After the
start-up, an air compressed by a gas turbine compressor or oxygen
separated from the compressed air by the air separator is used.
7. In an operation stage until about one fourth (1/4) load of the
gas turbine from the start-up operation, an incomplete coal
gasification fuel having a low calorific value is merely generated
in the coal gasification furnace. Such a coal gasification fuel is
not applicable to a gas turbine operation, and for this reason, the
fuel as described above has been conventionally supplied to the
combustor.
8. With a rise of load after that stage, in the coal gasification
furnace, a complete coal gasification fuel combustible in the
combustor is generated. In this stage, a a combustion operation of
using the liquid fuel is changed over to a combustion operation of
using the coal gasification fuel, and then, only coal gasification
fuel operation is carried out up to a gas turbine rating point.
9. As described above, the coal gasification fuel has a small
calorific value as compared with a liquid fuel or a natural gas.
Thus, in the case where a combustion gas temperature in the
combustor becomes low, a lot of carbon monoxide is discharged, and
therefore, there is a problem in operational characteristics during
a low load operation. For this reason, in the case where the gas
turbine is in a load dump state or when the gas turbine is stopped,
the operation change-over is again made from the operation of using
the coal gasification fuel to the operation of using only the
liquid fuel.
10. FIG. 10 is a view schematically showing an entire structure of
a combustor included in the aforesaid coal gasification combined
cycle power generation plant, and FIG. 11 is an enlarge sectional
view showing a fuel nozzle section of the combustor.
11. As shown in FIG. 10, a combustor 1 is constructed in a manner
that a combustor liner 4 used as an inner cylindrical casing is
inserted into an outer cylindrical casing 2 with a combustion air
passage 3 defined therebetween, a fuel nozzle 5 is provided on an
end portion on an upstream side of the combustor liner 4, and a
transition piece 6 is connected to a downstream side of the
combustor liner 4. An inner circumferential portion of the outer
cylindrical casing 2 is provided with a flow sleeve 7 which covers
the combustion air passage 3 and functions as an air guide.
12. The fuel nozzle 5 has a multiple cylindrical structure fixed to
a head plate 8 provided on the end portion of the outer cylindrical
casing 2. Further, the fuel nozzle 5 is provided, at its outer end
positioned on the outside thereof, with a liquid fuel supply port 9
for supplying a liquid fuel, an atomization air supply port 10 for
supplying an atomization air for atomizing the liquid fuel, and a
coal gasification fuel supply port 11 for supplying a coal
gasification fuel.
13. As shown in FIG. 11, the fuel nozzle 5 is formed with a liquid
fuel passage 12 for passing the liquid fuel at the center portion
on the internal side thereof, an atomization air passage 13 for
passing an atomization air of the liquid fuel at the outer side of
the liquid fuel passage 12, and further, a coal gasification fuel
passage 14 for passing the coal gasification fuel at the outer side
of the atomization air passage 13. These passages 12, 13 and 14 are
arranged side-by-side in a manner of being partitioned by
cylindrical walls 15 and 16 and communicate with the liquid fuel
supply port 9, the atomization air supply port 10 and the coal
gasification fuel supply port 11, respectively.
14. Moreover, an inner end portion of the fuel nozzle 5 facing the
inside of the combustor liner 4 is provided with a liquid fuel
injection port 17 for injecting a liquid fuel "a" from the liquid
fuel passage 12, an atomization air injection port 18 which injects
an atomization air "b" around the liquid fuel injection port 17
from the atomization air passage 13 so that the liquid fuel "a"
becomes an atomized state, and a coal gasification fuel injection
port 20 having a swirler 19 which injects a coal gasification fuel
"c" from the coal gasification fuel passage 14 in a rotating
state.
15. During the gas turbine operation, the coal gasification fuel
"c" or the liquid fuel "a" in an air atomized state is selectively
injected into the combustor 5 from the fuel nozzle 5 by a known
means, and a combustion air "d" is supplied into the combustor
liner 4 from a gas turbine compressor (not shown) via the
combustion air passage 3 to thereby start the combustion. Then, a
combustion gas 21 thus generated is supplied to a gas turbine (not
shown) via the transition piece 6.
16. Meanwhile, as described above, conventionally, when the gas
turbine is in the stage of start-up, stop or during a load dump, a
combustion operation using only the liquid fuel "a" is carried out,
and at this time, the supply of the coal gasification fuel "c" is
stopped. For this reason, an internal pressure of the coal
gasification fuel passage 14 for supplying the coal gasification
fuel "c" becomes lower than that of the combustor liner 4 in which
the combustion gas 21 generated by the combustion of the liquid
fuel "a" is filled. Thus, as shown by an arrow "e" in FIG. 11, by
the differential pressure, there happens a phenomenon such that the
combustion gas 21 conversely flows into the coal gasification fuel
passage 14 from the combustor liner 4 side.
17. Even in the case where no differential pressure is caused, by a
mere change in a kinetic (dynamic) pressure of the combustion gas
21, a pressure change of the combustor 1 or the like, there may be
the case where the combustion gas 21 conversely flows into the coal
gasification passage 14.
18. The conversely flowing phenomenon of the combustion gas 21 as
described above is a factor of damaging the fuel nozzle 5, hinders
the gas turbine operation, and further, makes short the life of
combustor. For this reason, various problems are caused in an
operation, economics or the like.
SUMMARY OF THE INVENTION
19. An object of the present invention is to eliminate defects or
drawbacks encountered in the prior art described above and to
provide a coal gasification fuel combined cycle power generation
plant or facility and a method of operating the same which can
prevent a combustion gas from conversely flowing into a coal
gasification fuel supply passage during a liquid fuel operation and
can avoid damaging of a fuel nozzle so as to stably carry out a gas
turbine operation and to improve a usable life of the
combustor.
20. This and other objects can be achieved according to the present
invention by providing, in one aspect, a coal gasification combined
cycle power generation plant including a gas turbine system, a fuel
supply system, an air supply system and an exhaust gas system,
which are operatively connected to each other,
21. the gas turbine system including a combustor provided with
means for selectively burning a coal gasification fuel obtained by
gasifying a coal and a liquid fuel atomized by an atomization air
and a gas turbine to which a combustion gas generated in the
combustor is supplied, the combustor being provided with a fuel
nozzle, a liner disposed inside the combustor and a combustion air
passage formed between the liner and an outer casing of the
combustor,
22. the fuel supply system being provided with a liquid fuel supply
passage for the combustor through the fuel nozzle, an atomization
air supply passage for the combustor through the fuel nozzle and a
coal gasification fuel supply passage for the combustor through the
fuel nozzle, all of the supply passages being arranged so as to be
adjacent to each other,
23. the atomization air supply passage being provided with an
outlet portion to which a branching outlet port for injecting the
atomization air toward an outlet portion of the coal gasification
supply passage is formed.
24. In another aspect, there is provided a coal gasification
combined cycle power generation plant including a gas turbine
system, a fuel supply system, an air supply system and an exhaust
gas system, which are operatively connected to each other,
25. the gas turbine system including a combustor provided with
means for selectively burning a coal gasification fuel obtained by
gasifying a coal and a liquid fuel atomized by an atomization air
and a gas turbine to which a combustion gas generated in the
combustor is supplied, the combustor being provided with a fuel
nozzle, a liner disposed inside the combustor and a combustion air
passage formed between the liner and an outer casing of the
combustor,
26. the fuel supply system being provided with a liquid fuel supply
passage for the combustor through the fuel nozzle, an atomization
air supply passage for the combustor through the fuel nozzle and a
coal gasification fuel supply passage for the combustor through the
fuel nozzle, all of the supply passages being arranged so as to be
adjacent to each other,
27. the atomization air supply passage being provided with a
passage wall portion and an outlet portion and a blowout hole for
blowing out the atomization air to the coal gasification fuel
supply passage in a vicinity of the outlet portion.
28. In a further aspect, there is provided a coal gasification
combined cycle power generation plant including a gas turbine
system, a fuel supply system, an air supply system and an exhaust
gas system, which are operatively connected to each other,
29. the gas turbine system including a combustor provided with
means for selectively burning a coal gasification fuel obtained by
gasifying a coal and a liquid fuel atomized by an atomization air
and a gas turbine to which a combustion gas generated in the
combustor is supplied, the combustor being provided with a fuel
nozzle, a liner disposed inside the combustor and a combustion air
passage formed between the liner and an outer casing of the
combustor,
30. the fuel supply system being provided with a liquid fuel supply
passage for the combustor through the fuel nozzle, an atomization
air supply passage for the combustor through the fuel nozzle and a
coal gasification fuel supply passage for the combustor through the
fuel nozzle, all of the supply passages being arranged so as to be
adjacent to each other,
31. the combustion air passage being provided with an outlet
portion through which a combustion air from a compressor of the gas
turbine system is blown toward the liner of the combustor and the
outlet portion is provided with a combustion air injecting portion
so as to inject a combustion air toward an outlet portion of the
coal gasification fuel supply passage.
32. In a still further aspect, there is provided a coal
gasification combined cycle power generation plant including a gas
turbine system, a fuel supply system, an air supply system and an
exhaust gas system, which are operatively connected to each
other,
33. the gas turbine system including a combustor provided with
means for selectively burning a coal gasification fuel obtained by
gasifying a coal and a liquid fuel atomized by an atomization air
and a gas turbine to which a combustion gas generated in the
combustor is supplied, the combustor being provided with a fuel
nozzle, a liner disposed inside the combustor and a combustion air
passage formed between the liner and an outer casing of the
combustor,
34. the fuel supply system being provided with a liquid fuel supply
passage for the combustor through the fuel nozzle, an atomization
air supply passage for the combustor through the fuel nozzle and a
coal gasification fuel supply passage for the combustor through the
fuel nozzle, all of the supply passages being arranged so as to be
adjacent to each other,
35. the combustion air passage being communicated with the coal
gasification fuel supply passage so as to supply a combustion air
to the coal gasification fuel supply passage from the combustion
air passage and a control means for controlling an air flow rate in
the coal gasification fuel supply passage is provided for the
combustion air passage.
36. In a preferred embodiment, the coal gasification combined cycle
power generation plant further includes a control unit provided for
the coal gasification fuel supply passage, the control unit, which
may include a normal operation flow control means for controlling a
flow rate in a coal gasification fuel operation and an auxiliary
flow control means for controlling a flow rate of a little amount
of the coal gasification fuel supplied in a use of the liquid fuel.
A temperature detector may be further provided for the fuel nozzle
for injecting the coal gasification fuel to the combustor and a
further control means for controlling the auxiliary flow control
means which operates in a case where the temperature detector
detects a temperature more than a fixed temperature, and the
further control means is set so as to secure a minimum flow rate
for preventing the coal gasification fuel from conversely flowing
into the fuel nozzle.
37. The above object can be also achieved by providing, in a still
further aspect, a method of operating a coal gasification combined
cycle power generation plant including a gas turbine system, a fuel
supply system, an air supply system and an exhaust gas system,
which are operatively connected to each other, the gas turbine
system including a combustor provided with means for selectively
burning a coal gasification fuel obtained by gasifying a coal and a
liquid fuel atomized by an atomization air and a gas turbine to
which a combustion gas generated in the combustor is supplied, the
combustor being provided with a fuel nozzle, a liner disposed
inside the combustor and a combustion air passage formed between
the liner and an outer casing of the combustor, the fuel supply
system being provided with a liquid fuel supply passage for the
combustor through the fuel nozzle, an atomization air supply
passage for the combustor through the fuel nozzle and a coal
gasification fuel supply passage for the combustor through the fuel
nozzle, all of the supply passages being arranged so as to be
adjacent to each other, the operation method comprising the steps
of:
38. carrying out an operation by the combustion of the liquid fuel
during a start-up of the gas turbine;
39. carrying out an operation by the combustion of the coal
gasification fuel after a predetermined time elapsed thereafter;
and
40. supplying an incomplete coal gasification fuel from the coal
gasification fuel supply passage to the combustor through the fuel
nozzle until a coal gasification fuel operation from the start-up
of the gas turbine.
41. In a still further aspect, there is provided a method of
operating a coal gasification combined cycle power generation plant
including a gas turbine system, a fuel supply system, an air supply
system and an exhaust gas system, which are operatively connected
to each other, the gas turbine system including a combustor
provided with means for selectively burning a coal gasification
fuel obtained by gasifying a coal and a liquid fuel atomized by an
atomization air and a gas turbine to which a combustion gas
generated in the combustor is supplied, the combustor being
provided with a fuel nozzle, a liner disposed inside the combustor
and a combustion air passage formed between the liner and an outer
casing of the combustor, the fuel supply system being provided with
a liquid fuel supply passage for the combustor through the fuel
nozzle, an atomization air supply passage for the combustor through
the fuel nozzle and a coal gasification fuel supply passage for the
combustor through the fuel nozzle, all of the supply passages being
arranged so as to be adjacent to each other, the operation method
comprising the steps of:
42. carrying out an operation by the combustion of the liquid fuel
during a start-up of the gas turbine;
43. carrying out an operation by the combustion of the coal
gasification fuel after a predetermined time elapsed
thereafter;
44. changing over the coal gasification fuel operation into an
operation by the combustion of the liquid fuel in a case where a
gas turbine load becomes less than a fixed load; and
45. supplying the coal gasification fuel of a fixed amount from the
coal gasification fuel supply passage to the combustor through the
fuel nozzle after a change-over is made from a combustion operation
by the coal gasification fuel to a combustion operation by the
liquid fuel.
46. In a still further aspect, there is provided a method of
operating a coal gasification combined cycle power generation plant
including a gas turbine system, a fuel supply system, an air supply
system and an exhaust gas system, which are operatively connected
to each other, the gas turbine system including a combustor
provided with means for selectively burning a coal gasification
fuel obtained by gasifying a coal and a liquid fuel atomized by an
atomization air and a gas turbine to which a combustion gas
generated in the combustor is supplied, the combustor being
provided with a fuel nozzle, a liner disposed inside the combustor
and a combustion air passage formed between the liner and an outer
casing of the combustor, the fuel supply system being provided with
a liquid fuel supply passage for the combustor through the fuel
nozzle, an atomization air supply passage for the combustor through
the fuel nozzle and a coal gasification fuel supply passage for the
combustor through the fuel nozzle, all of the supply passages being
arranged so as to be adjacent to each other, the operation method
comprising the steps of:
47. carrying out an operation by the combustion of the liquid fuel
during a start-up of the gas turbine;
48. carrying out an operation by the combustion of the coal
gasification fuel after a predetermined time elapsed
thereafter;
49. changing over the coal gasification fuel operation into an
operation by the combustion of the liquid fuel at the same time
with a load dump in a case of a load dump; and
50. supplying the coal gasification fuel of a fixed amount from the
coal gasification fuel passage to the combustor through the a fuel
nozzle after a change-over is made from a combustion operation by
the coal gasification fuel to a combustion operation by the liquid
fuel.
51. The above operation methods may further comprise the step of
controlling a flow rate in a coal gasification operation, the
controlling step may including normal controlling of a flow rate in
a coal gasification fuel operation and auxiliary controlling of a
flow rate of a little amount of the coal gasification fuel supplied
in a use of the liquid fuel.
52. The auxiliary flow control is controlled, in a case where a
temperature more than a fixed temperature is detected, so as to
secure a minimum flow rate for preventing the coal gasification
fuel from conversely flowing into the fuel nozzle.
53. According to the characters or subject features of the present
invention mentioned above, it becomes possible to prevent the
combustion gas from conversely flowing into the coal gasification
fuel supply passage during the liquid fuel operation. Therefore,
the fuel nozzle is prevented from being damaged, whereby the gas
turbine operation can be stably carried out and the usable life of
the combustor can be effectively increased.
54. The nature and further detailed features of the present
invention will be made more clear from the following descriptions
made with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
55. In the accompanying drawings:
56. FIG. 1 shows a system diagram of a coal gasification combined
cycle power generation plant according to a first embodiment of the
present invention;
57. FIG. 2 is a sectional view showing a structure of a gas turbine
combustor in the first embodiment;
58. FIG. 3 is a partially enlarged view of the gas turbine
combustor shown in FIG. 2;
59. FIG. 4 shows a sectional view of a gas turbine combustor
according to a second embodiment of the present invention;
60. FIG. 5 shows a sectional view of a gas turbine combustor
according to a third embodiment of the present invention;
61. FIG. 6 shows a sectional view of a gas turbine combustor
according to a fourth embodiment of the present invention;
62. FIG. 7 is a graph showing a fuel flow characteristic to explain
a fifth embodiment of the present invention;
63. FIG. 8 is a graph showing a fuel flow characteristic to explain
a sixth embodiment of the present invention;
64. FIG. 9 shows a system diagram of a coal gasification combined
cycle power generation plant according to a seventh embodiment of
the present invention;
65. FIG. 10 is a sectional view schematically showing a
conventional gas turbine combustor; and
66. FIG. 11 is a partially sectional view showing the gas turbine
combustor shown in FIG. 10.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
67. Embodiments of the present invention will be described
hereunder with reference to the accompanying drawings.
FIRST EMBODIMENT (FIG. 1 to FIG. 3)
68. FIG. 1 is a system diagram showing the whole construction of a
coal gasification combined cycle power generation plant of facility
of the first embodiment of the present invention.
69. With reference to FIG. 1, the coal gasification combined cycle
power generation plant of this first embodiment comprises a gas
turbine system 31, a fuel supply system 32, an air supply system 33
and a an exhaust gas system 34, which are broadly classified and
operatively connected to each other.
70. The gas turbine system 31 includes a combustor 35 which can
selectively burn the coal gasification fuel "c" and the liquid fuel
"a", a gas turbine 36 which is driven by a combustion gas generated
by the combustor 35, a gas turbine compressor 37 which is provided
coaxially with the gas turbine 36, and a generator 38. The
selection of the coal gasification fuel and the liquid fuel is
performed by a known means under the monitoring of the liquid fuel
from the combustion start time.
71. The fuel supply system 32 is composed of two systems, that is,
a coal gasification fuel supply system 32a and a liquid fuel supply
system 32b. The coal gasification fuel supply system 32a includes a
gasification furnace 39 for gasifying coal, and a gas refinery
equipment 40 for purifying a coal gas refined by the gasification
furnace 39. Further, the coal gasification fuel supply system 32a
supplies the refined coal gasification fuel "c" to the combustor 35
via a coal gasification fuel pipe 41. The coal gasification fuel
pipe 41 is provided with a flow control valve 42 which functions as
a flow control unit.
72. The liquid fuel supply system 32b selectively supplies the
liquid fuel "a" and the atomization air "b" from a liquid fuel
supply source (not shown) and a atomization air supply source (not
shown), and the coal gasification fuel "c" to the combustor 35 via
a liquid fuel pipe 43 and an air pipe 44.
73. The air supply system 33 is a system for supplying oxygen
required for coal gasification in the gasification furnace 39.
Further, the air supply system 33 has an extraction pipe 45 for
extracting a part of compressed air from a gas turbine compressor
37, an air separator 46 which is connected to the extraction pipe
45 and generates oxygen, and an oxygen gas compressor 48 connected
to the air separator 46 via an oxygen gas pipe 47. Further, in the
air supply system 33, there is provided an auxiliary compressor 49
for generating oxygen used in the gasification furnace 39 before
the gas turbine compressor 37 is operated.
74. The exhaust gas system 34 includes an exhaust gas pipe 50
connected to the gas turbine 36, an exhaust gas boiler 51 connected
to the exhaust gas pipe 50 and a chimney stack 52.
75. In the case of operating the coal gasification combined cycle
power generation plant constructed in the manner described above,
first, the liquid fuel "a" and the atomization air "b" are supplied
to the combustor 35 to make combustion, and thereby, the gas
turbine 36 starts up. With the start-up of the gas turbine 36, the
coal gasification fuel is generated in the gasification furnace 39.
In this case, during the start-up of the gas turbine 36, at first,
in the gasification furnace 39, a compressed air from the auxiliary
compressor 49 or oxygen separated from the compressed air by the
air separator 46 is used. After the gas turbine 36 starts up, the
pressurized air by the gas turbine compressor 37 or oxygen
separated from the pressurised air by the air separator 46.
76. In the operation stage until about one-fourth (1/4) load of the
gas turbine 36 from the start-up operation, only incomplete coal
gasification fuel having a low calorific value is generated in the
gasification furnace 39, and for this reason, the liquid fuel
operation is continued. With the rise of load, a complete coal
gasification fuel is generated in the gasification furnace 39, and
thereafter, a change-over is made from the liquid fuel combustion
operation to a coal gasification fuel operation, and then, only
coal gasification fuel operation is carried out by a gas turbine
rating point. Thereafter, in the case where the gas turbine 36 is
in a load dump state or when the gas turbine 36 is stopped, a
change-over is again made from the coal gasification fuel operation
to the liquid fuel operation.
77. Next, the structure of the combustor 35 used in the coal
gasification combined cycle power generation plant will be
explained with reference to FIG. 2 and FIG. 3.
78. As shown in FIG. 2, a combustor 35 is constructed in a manner
that a combustor liner 64 used as an inner cylindrical casing is
inserted into an outer cylindrical casing 62 with a combustion air
passage 63 defined therebetween, a fuel nozzle 65 is provided at an
end portion on an upstream side of the combustor liner 64, and a
transition piece 66 is connected to a downstream side of the
combustor liner 64. An inner circumferential portion of the outer
cylindrical casing 62 is provided with a flow sleeve 67 which
covers the combustion air passage 63 and functions as an air
guide.
79. The fuel nozzle 65 has a multiple cylindrical shape fixed to a
head plate 68 provided on the end portion of the outer cylindrical
casing 62. Further, the fuel nozzle 65 is provided with a liquid
fuel supply port 69 for supplying a liquid fuel "a", an atomization
air supply port 70 for supplying an atomization air for atomizing
the liquid fuel "a", and a coal gasification fuel supply port 71
for supplying a coal gasification fuel "c", at its outer end
situated on the outer side of the outer cylindrical casing 62.
80. As shown in FIG. 3, the fuel nozzle 65 is formed with a liquid
fuel passage 72 for passing the liquid fuel "a" at the center
portion on the internal side thereof, an atomization air passage 73
for passing an atomization air "b" of the liquid fuel at the outer
side of the liquid fuel passage 72, and further, a coal
gasification fuel passage 74 for passing the coal gasification fuel
"c" at the outer side of the atomization air passage 73. These
passages 72, 73 and 74 are arranged side-by-side in a manner of
being partitioned by cylindrical walls 75 and 76 and communicate
with the liquid fuel supply port 69, the atomization air supply
port 70 and the coal gasification fuel supply port 71,
respectively.
81. Moreover, an inner end portion of the fuel nozzle 65 facing the
inside of the combustor liner 64 is provided with a liquid fuel
injection port 77 for injecting the liquid fuel "a" from the liquid
fuel passage 72, an atomization air injection port 78 which injects
the atomization air "b" around the liquid fuel injection port 77
from the atomization air passage 73 so that the liquid fuel "a"
becomes an atomized state, and a coal gasification fuel injection
port 80 having a swirler 79 which injects the coal gasification
fuel "c" from the coal gasification fuel passage 74 in a rotating
state.
82. As described above, the fuel nozzle 65 for injecting a fuel to
the combustor 35 is provided with the liquid fuel passage 72, the
atomization air passage 73 and the coal gasification fuel passage
74, which are arranged so as to be adjacent to each other. In this
embodiment, a branching outlet port 81 for injecting the
atomization air "b" toward the coal gasification injection port 80
situated on the outside is provided at a position of the injection
port 78 which is an outlet portion of the atomization air passage
73. A plurality of the branching outlet ports 81 for the
atomization air are formed along a circumferential direction of the
fuel nozzle 65 and continuously inject the atomization air "b"
toward the outside of the swirler 79 of the coal gasification fuel
injection port 80 so that an air film is formed on the coal
gasification fuel injection port 80.
83. Therefore, during the start-up state of the gas turbine 36,
during the load dump state or during the interruption of the gas
turbine, in the case of carrying out an operation in accordance
with the combustion by only the liquid fuel "a", even if the coal
gasification fuel "c" is not supplied to the coal gasification fuel
passage 74, and as a result, the internal pressure of the coal
gasification fuel passage 74 is lower than the combustion gas
pressure of the combustor 35, the coal gasification fuel passage 74
is shielded from the interior of the combustor liner 64 by an air
film formed by a part of the atomization air "b" injected from the
branching outlet port 81 for the atomization air "b". Therefore,
the combustion gas does not conversely flow into the coal
gasification fuel passage 74.
84. Furthermore, during the operation made by using the coal
gasification fuel "c", the supply of the liquid fuel "a" and the
atomization air "b" is stopped, and therefore, there is no
hindrance in injection and combustion of the coal gasification fuel
"c".
85. According to the first embodiment mentioned above, it is
possible to securely prevent the combustion gas from conversely
flowing into the coal gasification fuel passage 74 during the
liquid fuel operation. Therefore, the gas turbine operation can be
stably carried out without damaging the fuel nozzle 65 and the life
of the combustor can be made long. As a result, great advantage is
obtainable in both the viewpoints of operation and economics as
compared with the conventional power generation plant or
facility.
SECOND EMBODIMENT (FIG. 4)
86. FIG. 4 is an enlarged sectional view showing a fuel nozzle 65
of a combustor 35 of a coal gasification combined cycle power
generation plant according to a second embodiment of the present
invention.
87. As shown in FIG. 4, in this second embodiment, the fuel nozzle
65 for injection a fuel to the combustor 35 is provided with a
liquid fuel passage 72, an atomization air passage 73 and a coal
gasification fuel passage 74, which are arranged so as to be
adjacent to each other. Further, the fuel nozzle 65 is provided
with a blowout hole 82 for blowing out the atomization air to the
coal gasification fuel passage 74 at a passage wall 76 in the
vicinity of the outlet portion of the atomization air passage 73. A
plurality of the blowout holes 82 for atomization air are formed
along the circumferential direction of the fuel nozzle 65 and are
individually opened in the vicinity of the coal gasification fuel
passage injection port 80. For instance, the atomization air is
continuously blown out toward the inner surface of the swirler 79,
and thereafter, the atomization air "b" is injected from the coal
gasification fuel outlet port 80 into the combustor liner 64.
Further, the other construction is the substantially same as the
aforesaid first embodiment, and therefore, the same reference
numbers are used to designate the portions corresponding to those
shown in FIG. 3, and the details thereof are omitted herein.
88. In this second embodiment, during the start-up state of the gas
turbine 36, during the load dump state or during the interruption
of the gas turbine, in the case of carrying out an operation in
accordance with the combustion by only liquid fuel "a", even if the
coal gasification fuel is not supplied to the coal gasification
fuel passage 74, and as a result, the internal pressure of the coal
gasification fuel passage 74 is lower than the combustion gas
pressure of the combustor 35, the atomization air is blown out from
the blowout hole to the coal gasification fuel passage 74, so that
coal gasification fuel passage 74 becomes a pressurized state.
Therefore, the combustion gas does not conversely flow into the
coal gasification fuel passage 74.
89. Furthermore, during the operation made by using the coal
gasification fuel, the supply of the liquid fuel and the
atomization air is stopped, and therefore, there is no hindrance in
injection and combustion of the coal gasification fuel.
90. According to the second embodiment mentioned above, it is
possible to securely prevent the combustion gas from conversely
flowing into the coal gasification fuel passage 74 during the
liquid fuel operation. Therefore, the gas turbine operation can be
stably carried out without damaging the fuel nozzle 65 and the life
of the combustor can be made long. Accordingly, great advantage is
obtainable in both the viewpoints of operation and economics as
compared with the conventional plant or facility.
THIRD EMBODIMENT (FIG. 5)
91. FIG. 5 is an enlarged sectional view showing a fuel nozzle 65
of a combustor 35 of a coal gasification combined cycle power
generation plant according to a third embodiment of the present
invention.
92. As shown in FIG. 5, in this third embodiment, a combustion air
injecting portion 83 for injecting a combustion air "d" toward an
outlet portion of the coal gasification fuel passage 74 is provided
at an outlet portion of the combustion air passage 63 which blows
the combustion air "d" from the gas turbine compressor 37 (see FIG.
1) into the combustor liner 64. The combustion air injecting
portion 83 is composed of, for example, a hole 84 which is formed
at an end wall 64a on the fuel nozzle 65 side of the combustor
liner 64, and a guide member 85 which is disposed on the outer
peripheral side of the hole 84 and projects to the inner face of
the end wall 64a of the combustor liner 64. The combustion air is
continuously injected toward the outer side of the swirler 79 of
the coal gasification fuel injection port 80 so that an air film is
formed in the coal gasification fuel port 80.
93. Therefore, in this third embodiment, during the start-up state
of the gas turbine 36, during the load dump state or during the
interruption of the gas turbine, in the case of carrying out an
operation in accordance with the combustion by only the liquid fuel
"a", even if the coal gasification fuel "c" is not supplied to the
coal gasification fuel passage 74. As a result, the internal
pressure of the coal gasification fuel passage 74 is lower than the
combustion gas pressure of the combustor 35, the coal gasification
fuel passage 74 is shielded from the interior of the combustor
liner 64 by the air film formed by the combustion air "d".
Therefore, the combustion gas does not conversely flow into the
coal gasification fuel passage 74.
94. According to the third embodiment mentioned above, it is
possible to securely prevent the combustion gas from conversely
flowing into the coal gasification fuel passage 74 during the
liquid fuel operation. Therefore, the gas turbine operation can be
stably carried out without damaging the fuel nozzle 65, and the
life of the combustor can be made long. Accordingly, great
advantage is obtainable in both the viewpoints of operation and
economics in the same manner as that of the first embodiment.
FOURTH EMBODIMENT (FIG. 6)
95. FIG. 6 is an enlarged sectional view showing a combustor 35 of
a coal gasification combined cycle power generation plant according
to a fourth embodiment of the present invention.
96. As shown in FIG. 6, in this fourth embodiment, a combustion air
injecting portion 86 for injecting a combustion air "d" toward an
outlet portion of the coal gasification fuel passage 74 is provided
at an outlet portion of the combustion air passage 63 which blows
the combustion air "d" from the gas turbine compressor 37 into the
combustor liner 64. The combustion air injecting portion 86 is
constructed in a manner that the combustion air passage 63 and the
coal gasification fuel passage 74 communicates with each other by
means of a pipe 87 penetrating through the head plate 68, and the
pipe 87 is provided with a control valve 88.
97. With the construction as described above, the combustion air
"d" is supplied to the coal gasification fuel passage 74 via the
pipe 87 provided on the head plate 68. Thus, in the case where the
coal gasification fuel "c" is not supplied to the coal gasification
fuel passage 74, the control valve 88 is opened so that the
combustion air "d" is blown into the combustor liner 64 from the
coal gasification fuel passage 74 via the swirler 79. Thus, it
becomes possible to prevent the combustion gas from conversely
flowing into the coal gasification fuel passage 74 as like as in
the above-mentioned embodiments.
98. Moreover, in this fourth embodiment, at the time when the
supply of the coal gasification fuel "c" is started, in the case
where a pressure of the combustion air "d" side is high, the
combustion air "d" is mixed with the coal gasification fuel "c" in
the coal gasification fuel passage 74, and then, becomes a
premixing lean fuel. For this reason, there is the possibility that
combustion happens in the coal gasification fuel passage 74.
Further, conversely, in the case where the pressure of the coal
gasification fuel "c" is higher than the pressure of the combustion
air "d", there is the possibility that the coal gasification fuel
"c" flows from the coal gasification fuel passage 74 into the
combustion air passage 63 side.
99. Considering the above situation, in this fourth embodiment, the
control valve 88 provided on the pipe 87 is closed during the coal
gasification fuel operation so as to make a closed state. Further,
a check valve (not shown) may be used so as to prevent the
combustion air from conversely flowing to the combustion air
passage 63 side.
100. In the fourth embodiment mentioned above, it is possible to
securely prevent the combustion gas from conversely flowing into
the coal gasification fuel passage 74 during the liquid fuel
operation. Thus, the same operations and effects as those of the
respective embodiments mentioned above can be obtained.
FIFTH EMBODIMENT (FIG. 1 and FIG. 7)
101. This fifth embodiment shows an operating method of the coal
gasification fuel combined cycle power generation plant according
to the present invention. In particular, an incomplete coal
gasification fuel is supplied to the coal gasification fuel
passage, and thereby, there is provided an operating method of
preventing the combustion gas from conversely flowing into the coal
gasification fuel passage during the liquid fuel operation until
the coal gasification fuel operation from the gas turbine
start-up.
102. More specifically, for example, in the case of operating the
coal gasification fuel combined cycle power generation plant shown
in FIG. 1, an operation is made by the combustion by only the
liquid fuel "a" until the gas turbine load becomes about one fourth
(1/4) load from the start-up of the gas turbine 36, and thereafter,
the operation is changed into an operation by a complete coal
gasification fuel "c". The coal gasification fuel generated in the
gasification furnace 39 until the load operation of the aforesaid
load is incomplete and is not burned.
103. Conventionally, the supply of the incomplete coal gasification
fuel has been stopped during the liquid fuel operation until the
gas turbine load becomes one fourth (1/4) load from the gas turbine
start-up. However, in this fifth embodiment, during the liquid fuel
operation, the incomplete coal gasification fuel "c" is supplied
from the coal gasification fuel passage to the combustor 35 via the
fuel nozzle 35.
104. FIG. 7 is a graph showing a fuel flow rate to explain the
operating method mentioned above and taking a flow rate of liquid
fuel and coal gasification fuel as an ordinate and taking a gas
turbine load as an abscissa.
105. As shown in FIG. 7, in this fifth embodiment, the incomplete
coal gasification fuel generated in the gasification furnace 39 is
gradually supplied to the combustor together with a liquid fuel
whose supplying flow rate gradually increases from the start-up. In
other words, with the increase of the liquid fuel flow rate, the
combustion gas increases, and then, the internal pressure of the
combustor liner is made high. With the high pressure the combustor
liner, the supply of incomplete coal gasification fuel is increased
so that an internal pressure of the coal gasification fuel passage
is made high. According to this function, it is possible to prevent
the combustion gas from conversely flowing into the coal
gasification fuel passage.
106. The operation is changed into a coal gasification fuel
operation at the time when the complete coal gasification fuel "c"
is generated in the gasification furnace 39, and then, from this
set time, the flow rate of the liquid fuel is gradually reduced.
After that, the flow rate of the coal gasification fuel is
increased until the rating load, and thereafter, the operation is
carried out at a fixed flow rate.
107. According to the operating method of this embodiment, in
particular, the fuel nozzle has no need of change in its structure.
Further, only through the fuel supply control, it becomes possible
to securely prevent the combustion gas from conversely flowing into
the coal gasification fuel passage, as like as in the
above-mentioned embodiments. Therefore, the gas turbine operation
can be stably carried out, and the life of the combustor can be
made long. As a result, great advantage is obtainable in both the
viewpoints of operation and economics of the power generation plant
or facility.
SIXTH EMBODIMENT (FIG. 1)
108. This sixth embodiment shows an operating method of the coal
gasification fuel power generation plant of the present invention.
There is provided an operating method of preventing the combustion
gas from conversely flowing into the coal gasification fuel passage
74 by supplying the coal gasification fuel to the coal gasification
fuel passage during the liquid fuel operation in the case where a
load becomes lower than a fixed load as the gas turbine stop
operation.
109. More specifically, in the case of operating the coal
gasification fuel combined cycle power generation plant shown in
FIG. 1, as described in the fifth embodiment mentioned above, after
the gas turbine load becomes about one fourth (1/4) load, an
operation using the complete coal gasification fuel "c" is carried
out, and after that, the flow rate of the coal gasification fuel
"c" is increased until the rating load, and thereafter, the
operation is carried out at a fixed flow rate. In the case where
the gas turbine load becomes lower than a fixed load as the case
that the gas turbine is stopped, it is difficult to use the coal
gasification fuel "c". For this reason, the operation is changed
into an operation made by the combustion of the liquid fuel "a",
and after the change-over, the supply of the coal gasification fuel
"c" has been stopped in the conventional manner.
110. However, in this sixth embodiment, even during the liquid fuel
operation, the coal gasification fuel is supplied to the combustor
from the coal gasification fuel passage via the fuel nozzle.
111. According to the operating method of this embodiment, in
particular, the fuel nozzle and the like have no need of change in
their structure. Further, through only the fuel supply control, it
becomes possible to securely prevent the combustion gas from
conversely flowing into the coal gasification fuel passage as like
as in the above-mentioned embodiments. Therefore, the gas turbine
operation can be stably carried out, and the life of the combustor
can be made long. As a result, great advantage is obtainable in
both the viewpoints of operation and economics of the power
generation plant or facility.
SEVENTH EMBODIMENT (FIG. 8)
112. This seventh embodiment shows an operating method of the coal
gasification fuel combined cycle power generation plant according
to the present invention. There is provided a method of preventing
the combustion gas from conversely flowing into the coal
gasification fuel passage by supplying the coal gasification fuel
to the coal gasification fuel passage during the liquid fuel
operation in the case where a change-over is made from an operation
using the coal gasification fuel into an operation using the liquid
fuel during the gas turbine load dump state.
113. More specifically, in the case where the gas turbine load is
dumped during the coal gasification fuel operation, there is a need
of decreasing the fuel supply amount to prevent an over speed from
causing. In this case, it is difficult to carry out a combustion
operation by a little coal gasification fuel in view of
combustibility, and for this reason, the operation is changed into
an operation by the combustion of the liquid fuel. After the
change-over, the supply of the coal gasification fuel has been
stopped in the conventional manner.
114. However, in this seventh embodiment, even during the liquid
fuel operation, the coal gasification fuel is supplied to the
combustor from the coal gasification fuel passage via the fuel
nozzle.
115. FIG. 8 is a graph showing a fuel flow rate to explain the
operating method, and taking a flow rate of liquid fuel and coal
gasification fuel as an ordinate and taking a time as an
abscissa.
116. As shown by a solid-line curve in FIG. 8, in this seventh
embodiment, in the case where there is a load dump during the coal
gasification fuel operation, a flow rate of the coal gasification
fuel is reduced for a short time at the same time with the load
dump. Further, as shown by a broken-line curve, the operation is
changed into the liquid fuel operation. In this case, a little coal
gasification fuel continues to be supplied to the coal gasification
fuel passage without stopping the supply of the coal gasification
fuel. According to this operation, it becomes possible to prevent
the combustion gas from conversely flowing into the coal
gasification fuel passage.
117. According to the operating method of this embodiment, in
particular, the fuel nozzle has no need of change in its structure.
Further, through only the fuel supply control, it becomes possible
to securely prevent the combustion gas from conversely flowing into
the coal gasification fuel passage as like as in the respective
embodiments mentioned above. Therefore, the gas turbine operation
can be stably carried out, and the life of the combustor can be
made long. As a result, great advantage is obtainable in both the
viewpoints of operation and economics of the power generation plant
or facility.
EIGHTH EMBODIMENT (FIG. 9)
118. This eighth embodiment shows a coal gasification combined
cycle power generation plant which is preferable to the case of
carrying out the operating method described with respect to the
fifth to seventh embodiments and is an improvement in the coal
gasification combined cycle power generation plant of the first
embodiment shown in FIG. 1.
119. More specifically, according to the construction shown in FIG.
1, in the case of supplying the coal gasification fuel in order to
prevent the combustion gas from conversely flowing into the coal
gasification fuel passage during the liquid fuel operation, a flow
rate is controlled by means of the flow control valve 42 mounted to
the coal gasification fuel pipe 41. However, the flow control valve
42 is provided for controlling a flow rate of the coal gasification
fuel "c" during a normal operation and is constructed in a manner
that the flow rate of the coal gasification fuel "c" is controlled
to the 100% load flow rate. For this reason, the flow control valve
42 is not always suitable to the control of a little coal
gasification fuel "c" for preventing the combustion gas from
conversely flowing.
120. Considering such circumstances, in this eighth embodiment, as
shown in FIG. 9, the flow control unit provided on the coal
gasification fuel pipe 41 is divided into two systems. More
specifically, there is provided the flow control valve 42 which
functions as a normal operation flow control unit for controlling
the flow of the case of carrying out the coal gasification fuel
operation. In addition to the flow control valve 42, there is
provided an auxiliary flow control valve 89 which functions as an
auxiliary flow control unit in the case of supplying a little coal
gasification fuel "c" so as to prevent the combustion gas from
conversely flowing into the coal gasification fuel passage during
the liquid fuel operation. The other construction is the
substantially same as that shown in FIG. 1, and therefore, the same
reference numerals are used to designate parts corresponding to
those shown in FIG. 1 and the details thereof are omitted
herein.
121. As described above, the auxiliary flow control valve 89 for
controlling a little coal gasification fuel "c" is provided, and
thereby, it becomes possible to perform a precise flow control of
the necessary and minimum coal gasification fuel. Therefore, it is
possible to further improve a function of preventing the combustion
gas from conversely flowing into the coal gasification fuel
passage.
122. Further, in this eighth embodiment, there is provided a
temperature detector 90 in the fuel nozzle for injecting the coal
gasification fuel to the combustor 35 or at the vicinity thereof.
In the case where the temperature detector 90 detects a temperature
more than a fixed one, a control unit 91 for controlling the
auxiliary flow control valve is provided. The control unit is set
so as to secure the minimum flow rate for preventing the coal
gasification fuel from conversely flowing into the fuel nozzle
65.
123. According to the structures mentioned above, a temperature
rise of the coal gasification fuel passage is detected when the
combustion gas conversely flows into the fuel nozzle, and thereby,
it is possible to automatically supply the minimum flow rate of the
coal gasification fuel "c" for preventing the combustion gas from
conversely flowing to the coal gasification fuel passage.
124. As is evident from the above description, according to the
present invention, it is possible to prevent the combustion gas
from conversely flowing into the coal gasification fuel passage
during the liquid fuel operation. Thus, the fuel nozzle is
prevented from being damaged, so that the gas turbine operation can
be stably carried out.
125. It is also to be noted that the present invention is not
limited to the described embodiments and many other changes,
modification and combinations may be made without departing from
the scopes of the appended claims.
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