JPH07158407A - Steam turbine device for single-shaft type combined cycle plant - Google Patents

Abstract

PURPOSE:To make the shafting of a single-shaft type combined cycle plant compact so as to improve maintainability and accessibility and to improve the operability of the plant. CONSTITUTION:A steam connecting pipe 11 is connected from a medium pressure compartment 9 to a low pressure compartment 10. This steam connecting pipe 11 is fitted to the lower half parts of the medium pressure compartment 9 and low pressure compartment 10, and a low pressure steam feed-in pipe 12 is connected to the intermediate part of the steam connecting pipe 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine device in a large-capacity single-shaft combined cycle plant configured by connecting a gas turbine, a steam turbine and a generator on a single shaft.

[0002]

2. Description of the Related Art In recent years, in a thermal power plant due to global environmental problems, a combined use of a gas turbine, a waste heat recovery boiler, a steam turbine and a generator has been carried out for the purpose of saving fossil fuel and improving economical efficiency. Cycle demand is increasing. Among them, the single-shaft combined cycle in which a gas turbine, a steam turbine, and a generator are coaxially connected is often used because it has the advantage that only one generator is required and the starting and monitoring of the shaft system is simplified. Tend to

FIG. 6 shows an example of a conventional combined cycle plant. The compressor 1, the gas turbine 2, the generator 3 and the steam turbine 4 are arranged so that their rotors are located on one common axis. . The drive steam to the steam turbine is fed from the lower half side of the steam turbine 4 from the high pressure steam system 5, and the low pressure steam is further supplied to the low pressure steam system 6.
From the lower half near the low pressure part of the steam turbine 4,
The steam that has worked respectively flows from the low pressure exhaust chamber to the condenser (not shown).

[0004]

In the conventional combined cycle, the output of the steam turbine is about tens of thousands of kW, and since it is a non-reheat cycle, the steam turbine becomes a single-flow single-shaft type, and it is relatively easy to It is possible to send in half. However, in order to increase the capacity of the gas turbine and steam turbine, reheat cycle
The main steam and reheat steam temperatures can be raised to improve the thermal efficiency.
More than this (high pressure, high temperature part and low pressure, low temperature part) is required,
Similarly to the rotor, the vehicle compartment has two or more vehicle compartments. It cannot be said that a steam feeding method considering the maintainability of the steam turbine in such a single-shaft combined cycle has been established.

Further, in the case where a large number of shaft systems of the same type are arranged, each shaft system is started by a starter installed in each shaft, and effective startability and operability and necessary equipment and devices are provided. There was a problem in terms of complexity.

Therefore, an object of the present invention is to make a shaft system of a single-shaft combined cycle plant compact, improve maintainability and accessibility, and further improve plant operability. It is to provide a steam turbine device.

[0007]

SUMMARY OF THE INVENTION The present invention is characterized in that, in a single-shaft combined cycle plant, a pipe connecting the medium pressure compartment and the low pressure compartment is connected to the lower half side.

[0008]

In the steam turbine having the above-described structure, the steam inlet pipes and the steam communication pipes between the vehicle compartments are arranged in the lower half of the vehicle compartments. Alternatively, the passenger compartment can be opened without disassembling the steam communication pipe between the passenger compartments, and the turbine disassembly and assembly time can be shortened.

Further, in a plant having a multi-spindle system, such an arrangement makes it possible to easily connect the steam communication pipes between the vehicle compartments to each other, and to start steam from another shaft system at the time of start-up. By using, the startability can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 11 indicates a connecting pipe for guiding the steam leaving the medium-pressure casing 9 to the low-pressure casing 10. The steam communication pipe 11 is attached to the lower half of the medium pressure compartment 9 and the low pressure compartment 10, and a low pressure steam inlet pipe 12 is connected in the middle of the steam communication pipe 11.

Conventionally, the steam communication pipe 11 is attached to the upper half of the medium-pressure compartment 9 and the low-pressure compartment 10. Therefore, when opening both compartments 9 and 10 at the time of periodic inspection of the steam turbine, etc. After disassembling the steam communication pipe 11, it was necessary to disassemble the passenger compartments 9 and 10. However, according to the present invention, the steam communication pipe 11 is attached to the lower half of each of the vehicle compartments 9 and 10 to provide the steam communication pipe 11.
Since the vehicle compartments 9 and 10 can be opened without disassembling, the time required for disassembling and assembling the steam turbine can be shortened. Further, the steam can connect the low-pressure steam inlet pipe 12 that was connected to the medium-pressure casing 9 to the steam communication pipe 11, and the structure of the medium-pressure casing 9 can be simplified.

FIG. 2 shows the details of the connecting portion between the medium pressure compartment 9 and the steam communication pipe 11. Further, FIG. 3 shows details of the connecting portion between the steam communication pipe 11 and the low-pressure casing 10. FIG. 4 shows another embodiment of the present invention. This embodiment provides a method of starting the shaft system without a starter. Reference numeral 11 denotes a connecting pipe that guides the steam that has exited the medium-pressure casing 9 to the low-pressure casing 10, and the steam connecting pipe 11
Are connected to the lower half of the medium-pressure compartment 9 and the low-pressure compartment 10.
A stop valve 14 is provided in the middle of the steam communication pipe 11, and the steam communication pipe 11 on the side of the low-pressure casing 10 from the stop valve 14 is connected via the flow control valve 16 to the auxiliary steam pipe 13 from the auxiliary boiler and the stop valve 15. A low pressure steam inlet pipe 12 is connected.

At the time of starting the shaft system, the stop valve 14 and the stop valve 15 are closed, and the low pressure turbine is rotated by causing the flow control valve 16 to flow the auxiliary steam from the auxiliary boiler to the low pressure casing 10 while controlling the flow rate. , The axis system can be started. As a result, it becomes possible to start the shaft system without the starting device that was conventionally required when starting the shaft system.

FIG. 5 shows another embodiment to which the present invention is applied. The present embodiment provides a method of starting a shaft system having a multi-axis structure. In the figure, 11a and 11b are connecting pipes for connecting the steam exiting the medium-pressure vehicle compartments 9a and 9b to the low-pressure vehicle compartments 10a and 10b, and the vapor communication tubes 11a and 11b are the medium-pressure vehicle compartment 9
a, 9b and the lower half of the low-pressure vehicle compartments 10a, 10b. Stop valves 14a and 14b in the middle of the steam communication pipes 11a and 11b
The low-pressure steam inlet pipes 12a and 12b are connected to the steam communication pipes 11a and 11b of the stop valves 14a and 14b on the low-pressure casings 10a and 10b side via the stop valves 15a and 15b, respectively. Further, a steam pipe 17 and a flow rate control valve 18 for controlling the flow rate of steam flowing therethrough are provided between the steam communication pipe 11a and the steam communication pipe 11b.
In such a configuration, when the shaft system A is operating and the shaft system B is stopped, when the shaft system B is started, the stop valve 12b and the stop valve 14b are closed, the flow control valve 17 is adjusted, and the steam communication is performed. Tube 11
By flowing a part of the steam flowing through a into the low pressure casing 10b, the low pressure turbine of the shaft system B can be rotated and the shaft system B can be started.

In the case of a plant having a multi-spindle system, by connecting the connecting pipes of all shaft systems to each other as described above, when at least one shaft is operating, the steam of the system is used to start the other shaft. It can be performed.

[0016]

As described above, according to the present invention, the steam communication pipes of the steam turbine medium-pressure compartment and the low-pressure compartment are connected to the lower half of each compartment, and the own system or another shaft system is connected. By connecting to the system, the maintainability and operability of the plant can be improved.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a steam turbine device according to the present invention.

FIG. 2 is a cross-sectional view showing a connection portion between a medium-pressure compartment and a steam communication pipe.

FIG. 3 is an elevational view showing a connection portion between a steam communication pipe and a low-pressure cabin.

FIG. 4 is a system diagram showing another embodiment of the present invention.

FIG. 5 is a system diagram showing another embodiment of the present invention.

FIG. 6 is a configuration diagram showing a conventional single-shaft combined cycle plant.

[Explanation of symbols]

1 ... Compressor, 2 ... Gas turbine, 3 ... Generator, 4
... Steam turbines, 8,8a, 8b ... High-pressure cabin, 9,9
a, 9b ... Medium pressure compartment, 10 ... Low pressure compartment, 11, 11a, 11b ...
Steam connecting pipe, 12 ... Low-pressure steam inlet pipe, 13 ... Auxiliary steam pipe, 14
a, 14b, 15a, 15b ... Stop valve, 16, 18 ... Flow control valve.

Claims (4)

[Claims] 1. In a single-shaft combined cycle plant configured by connecting a gas turbine, a steam turbine, and a generator on a single shaft, a pipe connecting the medium-pressure part vehicle compartment and the low-pressure part vehicle compartment is connected to the lower half of the vehicle compartment. A steam turbine unit for a single-shaft combined cycle plant, which is connected to a steam turbine unit. 2. The steam turbine device for a single-shaft combined cycle plant according to claim 1, wherein the low-pressure steam feed system is directly connected to a pipe connecting the medium-pressure section vehicle compartment and the low-pressure section vehicle compartment. . 3. The steam turbine device for a single-shaft combined cycle plant according to claim 2, further comprising a valve on the side of the medium-pressure compartment of the pipe connecting the medium-pressure compartment and the low-pressure compartment. . 4. The uniaxial type according to claim 3, further comprising a pipe provided with a valve that connects the pipes that connect the medium pressure part vehicle compartment and the low pressure part vehicle compartment of a shaft system near or to each other. Steam turbine equipment for combined cycle plants.