JPH0666155A - Outside combustion type gas turbine combined power plant - Google Patents

Abstract

PURPOSE:To prevent the surging of an air compressor which is generated by the selection trouble of a shut-off valve by substituting a check valve equipped with a locking mechanism for shut-off for the shut-off valve installed in a high pressure air piping for the communication between the outlet of the air compressor and an outside combustion furnace such as a pressurizing combustion boiler installed outside. CONSTITUTION:In a high pressure air piping 11 for the communication between the outlet of an axial flow air compressor 1 and a pressurizing combustion boiler 2, a check valve V8 is installed in substitution for a shut-off valve. The check valve V8 constitutes a locking mechanism for shut-off from a locking rod and a locking rod operating gear. Accordingly, when a plant trips and the shut-off valves V2 and V7 closed, and a shut-off edge V6 is opened, the discharged air of the air compressor 1 flows into the high pressure rod piping 11 which has a large capacity and communicate to the pressurizing combustion boiler 2 through the check valve V8, and the increase of the discharged air pressure and the generation of surging due to the pressure increase can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external combustion type gas turbine combined cycle power generation plant, and can be applied to a combined cycle power generation facility having an external combustion furnace such as a pressurized fluidized bed boiler outside.

[0002]

2. Description of the Related Art FIG. 3 shows an external combustion type gas turbine combined cycle power plant called a pressurized fluidized bed combustor (PFBC).
It is one system diagram. In the figure, reference numeral 1 is an axial air compressor, 2
Is a pressurized combustion boiler such as a pressurized fluidized bed boiler which is an external combustion furnace, 3 is a filter, 4 is a gas expander, 5 is a generator, 6 is a steam turbine, 7 is a generator, 8 is a condenser, 9 is a condensate pump, 10 is an auxiliary combustor, V1 to V3 are cutoff valves, V4 is a steam stop valve, V5 is a steam control valve, V6 and V
Reference numeral 7 is a shutoff valve.

The air compressed by the axial air compressor 1 burns coal in a pressurized combustion boiler 2 to a high temperature and is used for steam generation. The exhaust gas passes through a filter 3 and a gas expander 4 Flow into. The gas expander 4 drives the generator 5 together with the air compressor 1.

The steam generated in the pressurized combustion boiler 2 flows into the steam turbine 6 through the steam stop valve V4 and the steam control valve V5, and drives the generator 7. After that, the water is condensed by the condenser 8, and the condensate pump 9 and the feed water heater not shown in the figure,
It flows into the pressurized combustion boiler 2 via a deaerator, a water supply pump and the like.

When the plant is started, the shut-off valves V1 and V2 are closed, the shut-off valve V3 is opened, the compressed air is guided to the auxiliary combustor 10, the gas or liquid fuel is burned, and the gas expander 4 is driven. The distance between the turbine chamber and the boiler is usually about 10 to 100 m.

The valve state in FIG. 3 shows the operation, but when the plant trips, the shut-off valve V as shown in FIG.
1, V2 are closed, shutoff valves V6, V7 are opened, the discharge air of the air compressor 1 is bypassed to the gas expander 4, and the combustion gas and compressed air in the pressurized combustion boiler 2 and the piping are bypassed to the exhaust side. To be done. This is to prevent the gas expander shaft from overspeeding during a trip.

[0007]

The pressurized combustion boiler has an extremely large capacity as compared with an ordinary gas turbine combustor. The boiler is usually 10 to 100 m from the turbine room.
Installed at some distance, the compressed air piping capacity is extremely large. Therefore, if the shutoff valve V1 closes quickly during a plant trip, the air compressor discharge air pressure rises and the air compressor may rush into surging. On the other hand, the axial air compressor has a constant speed because the generator is connected,
Moreover, the change range of the air volume is smaller than that of the centrifugal type. In addition, since the discharge pressure is high, in the above case, the fluctuation of the discharge pressure becomes so large that surging occurs, which may make the plant operation impossible.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an external combustion type gas turbine combined cycle power plant capable of preventing surging of the air compressor during a plant trip.

[0009]

To solve the above problems, according to the present invention, it is installed in a high-pressure air pipe for communicating an air compressor outlet with an external combustion furnace such as a pressurized combustion boiler provided outside. There is provided an external combustion type gas turbine combined cycle power plant characterized in that the shut-off valve is replaced with a check valve having a shut-off lock mechanism.

[0010]

When the plant is tripped, the air discharged to the air compressor is not blocked because it communicates with the external combustion furnace through the check valve, and the discharge air pressure does not rise and surging does not occur. Further, during operation, the check valve shuts off the reverse flow from the pressurized combustion boiler to the air compressor. The check valve locking mechanism is used to close the check valve when only the gas turbine shaft system is operated alone at plant startup.

[0011]

FIG. 1 is a system diagram of an external combustion type gas turbine combined cycle power plant showing one embodiment of the present invention. In the figure, the same parts as those shown in FIG. Therefore, detailed description thereof will be omitted.

According to FIG. 1, a check valve V8 is installed in place of the shutoff valve V1 in the high-pressure air pipe 11 which connects the outlet of the axial air compressor 1 and the pressurized combustion boiler 2 to each other. . As a result, when the plant trips, the shutoff valves V2 and V7 are closed, and the shutoff valve V6 is opened, the air compressor 1
Discharge air can flow into the large-capacity high-pressure air pipe 11 leading to the pressurized combustion boiler 2 through the check valve V8,
The rise in discharge air pressure and the resulting surging will be prevented.

FIG. 2 shows an embodiment of the check valve V8. In the figure, 21 is a valve body, 22 is a valve body, and a lock rod 23 and a lock rod operating gear 24 form a shut-off lock mechanism. I am configuring.

According to the check valve having the shut-off lock mechanism shown in FIG. 2, the lock mechanism is released during normal operation and acts like a normal check valve, so that the pressurized combustion boiler 2 is operated by air. If there is a reverse flow to the compressor 1, this is shut off.
On the other hand, when the gas turbine shaft system alone is operated as in the case of starting the plant, the lock rod 23 is inserted as shown by the alternate long and short dash line in FIG. 2 to fix the valve body 22 to the valve closed position.

[0015]

According to the present invention, during a plant trip,
Due to the malfunction of the shutoff valve switching, the surging of the air compressor, which has conventionally occurred, is almost completely prevented. Therefore, the reliability of the external combustion type gas turbine combined cycle power plant can be improved.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of an external combustion gas turbine combined cycle power plant according to the present invention.

FIG. 2 is a cross-sectional view showing an example of a main part of an external combustion gas turbine combined cycle power plant according to the present invention.

FIG. 3 is a system diagram during normal operation showing an embodiment of a conventional external combustion gas turbine combined cycle power plant.

FIG. 4 is a system diagram showing a turbine trip of the external combustion gas turbine combined cycle power generation plant of FIG.

[Explanation of symbols]

 1 Axial Flow Air Compressor 2 Pressurized Combustion Boiler 11 High Pressure Air Piping V8 Check Valve 23 Lock Rod 24 Lock Operation Gear

Claims (1)

[Claims] 1. A shut-off valve installed in a high-pressure air pipe that connects an outlet of an air compressor and an external combustion furnace such as a pressurized combustion boiler provided outside to a check valve having a shut-off lock mechanism. An external combustion type gas turbine combined cycle power plant characterized by being replaced.