Power plants – Combustion products used as motive fluid – With safety device
Reexamination Certificate
2002-06-19
2004-01-20
Koczo, Michael (Department: 3746)
Power plants
Combustion products used as motive fluid
With safety device
C060S039182
Reexamination Certificate
active
06679046
ABSTRACT:
The entire disclosure of Japanese Patent Application No.2001-207266 filed on Jul. 9, 2001 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a single-shaft combined plant having a gas turbine and a steam turbine connected by a single shaft. More specifically, the invention relates to the single-shaft combined plant useful when a clutch is interposed between the gas turbine and the steam turbine.
2. Description of Related Art
A single-shaft combined plant, having a gas turbine and a steam turbine connected by a single shaft, is a plant with a high efficiency, involving minimal emission of hazardous substances (NOX, etc.), and flexibly accommodating diurnal changes in electric power consumption.
FIG. 3
is a configuration diagram of a conventional single-shaft combined plant. As shown in this drawing, a gas turbine
1
and a steam turbine
2
are connected by a single shaft
3
, and an electric generator (hereinafter referred to as a generator)
4
is also connected to the shaft
3
. Both a gas and an oil are available as fuels for the gas turbine
1
, and a fuel gas control valve
6
is provided on a fuel gas supply line
5
leading to the gas turbine
1
, while a fuel oil control valve
8
is provided on a fuel oil supply line
7
leading to the gas turbine
1
. These control valves
6
and
8
have their valve opening adjusted by adjustment of control oil pressures (pressures of operating oils), to thereby control the amounts of the fuel gas and the fuel oil supplied to the gas turbine
1
. A steam governing valve
10
is provided on a steam supply line
9
leading to the steam turbine
2
. The steam governing valve
10
also has its valve opening adjusted by adjustment of a control oil pressure (pressure of an operating oil), to thereby control the amount of steam supplied to the steam turbine
2
.
The above-described single-shaft combined plant is provided with an emergency shut-off oil system as shown in the drawing. That is, a fuel gas control valve emergency shut-off oil line
11
for shutting off the fuel gas control valve
6
, and a fuel oil control valve emergency shut-off oil line
12
for shutting off the fuel oil control valve
8
are present as gas turbine emergency shut-off oil lines. A fuel gas control valve tripping electromagnetic valve
13
is provided on the fuel gas control valve emergency shut-off oil line
11
, while a fuel oil control valve tripping electromagnetic valve
14
is provided on the fuel oil control valve emergency shut-off oil line
12
.
Thus, only the fuel gas control valve tripping electromagnetic valve
13
is closed (energized) to establish an emergency shut-off oil pressure for the fuel gas control valve
6
. As a result, the amount of the fuel gas supplied can be controlled by the fuel gas control valve
6
. When the fuel oil control valve tripping electromagnetic valve
14
is deenergized, the gas turbine
1
can be operated by the fuel gas. On the other hand, only the fuel oil control valve tripping electromagnetic valve
14
is closed (energized) to establish an emergency shut-off oil pressure for the fuel oil control valve
8
. As a result, the amount of the fuel oil supplied can be controlled by the fuel oil control valve
8
. When the fuel gas control valve tripping electromagnetic valve
13
is deenergized, the gas turbine
1
can be operated by the fuel oil.
A steam governing valve emergency shut-off oil line
15
for shutting off the steam governing valve
10
is provided as a steam turbine emergency shut-off oil line. A steam governing valve tripping electromagnetic valve
16
is provided on the steam governing valve emergency shut-off oil line
15
. When steam is to be supplied to the steam turbine
2
, the steam governing valve tripping electromagnetic valve
16
is closed (energized) to establish an emergency shut-off oil pressure for the steam governing valve
10
. As a result, the amount of steam supplied can be controlled by the steam governing valve
10
.
The steam governing valve tripping electromagnetic valve
16
is also connected to the fuel gas control valve emergency shut-off oil line
11
and the fuel oil control valve emergency shut-off oil line
12
via check valves
17
and
18
. The check valve
17
allows the flow of an emergency shut-off oil from the fuel gas control valve emergency shut-off oil line
11
toward the steam governing valve tripping electromagnetic valve
16
, but blocks its flow in the reverse direction, as indicated by arrows in the drawing. The check valve
18
allows the flow of an emergency shut-off oil from the fuel oil control valve emergency shut-off oil line
12
toward the steam governing valve tripping electromagnetic valve
16
, but blocks its flow in the reverse direction, as indicated by arrows in the drawing.
The tripping electromagnetic valves
13
,
14
and
16
of the emergency shut-off oil system are actuated by a protective interlock circuit (not shown) in the manner described below.
When the gas turbine
1
is to be operated by the fuel gas, only the fuel gas control valve tripping electromagnetic valve
13
is closed (energized) to enable only the fuel gas control valve
6
to work. On this occasion, the fuel oil control valve tripping electromagnetic valve
14
is kept open (unenergized) to prevent the fuel oil from being accidentally supplied to the gas turbine
1
. When the gas turbine
1
is to be operated by the fuel oil, on the other hand, only the fuel oil control valve tripping electromagnetic valve
14
is closed (energized) to enable only the fuel oil control valve
8
to work. On this occasion, the fuel gas control valve tripping electromagnetic valve
13
is kept open (unenergized) to prevent the fuel gas from being accidentally supplied to the gas turbine
1
.
With the conventional single-shaft combined plant, the gas turbine
1
and the steam turbine
2
are started together. For this purpose, the fuel gas control valve tripping electromagnetic valve
13
or the fuel oil control valve tripping electromagnetic valve
14
is closed (energized) to start the gas turbine
1
. At the same time, the steam governing valve tripping electromagnetic valve
16
is also closed (energized) to make the steam governing valve
10
operable, thereby starting the steam turbine
2
as well.
When the gas turbine
1
is to be stopped, the energized fuel gas control valve tripping electromagnetic valve
13
(or the fuel oil control valve tripping electromagnetic valve
14
) is opened to release the emergency shut-off oil from the fuel gas control valve
6
(or the fuel oil control valve
8
) via the fuel gas control valve emergency shut-off oil line
11
(or the fuel oil control valve emergency shut-off oil line
12
). As a result, the control oil (operating oil) escapes to shut off the fuel gas control valve
6
(or the fuel oil control valve
8
), thereby stopping the supply of the fuel gas (or the fuel oil). When the steam turbine
2
is to be stopped, the energized steam governing valve tripping electromagnetic valve
16
is also opened to release the emergency shut-off oil from the steam governing valve
10
via the steam governing valve emergency shut-off oil line
15
. As a result, the control oil (operating oil) escapes to shut off the steam governing valve
10
, thereby stopping the supply of steam.
With the conventional single-shaft combined plant, moreover, it is not common practice to stop only the steam turbine
2
while keeping the gas turbine
1
working. Therefore, the steam governing valve tripping electromagnetic valve
16
is connected to the fuel gas control valve emergency shut-off oil line
11
and the fuel oil control valve emergency shut-off oil line
12
via the check valves
17
and
18
, as described above. Because of this structure, when the steam governing valve tripping electromagnetic valve
16
is opened (deenergized), not only the emergency shut-off oil of the steam governing valve
10
, but also the emergency sh
Matsuoka Miharu
Tanaka Satoshi
Koczo Michael
Mitsubishi Heavy Industries Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
LandOfFree
Single-shaft combined plant does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Single-shaft combined plant, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Single-shaft combined plant will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3207472