JPH0828298A - Combined plant - Google Patents

Abstract

PURPOSE:To provide a combined plant, having a valve system, which is constituted to smooth the starting and the stop of a gas turbine and a pressure fluidized bed boiler and have high reliability. CONSTITUTION:A compressor outlet valve 2 of three-way valve structure is installed in a compressor outlet pipe 1 and one of the flow passage thereof is connected to a pressure fluidized bed boiler 3 and the other thereof to a combustor 4 for starting coupled to the gas turbine inlet pipe 6 of a gas turbine. A line 10 having a purge boost valve 11 is installed between the compressor outlet pipe 1 and a pipe 9 and a line 13 having a compressor outlet bypass valve 14 is installed between the compressor outlet pipe 1 and a pipe 12. Further, a line 7 having a boiler bypass valve 8 is installed between the compressor outlet pipe 1 and the gas turbine inlet pipe 6. The lines 10 and 13 performs backup of control of the compressor outlet valve 2 and the line 7 has a function to prevent the occurrence of surging of a compressor during the stop of the gas turbine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a pressurized fluidized bed boiler (P
The present invention relates to a combined plant capable of smoothly starting and stopping an FBC) and a gas turbine.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional system diagram around a valve for starting and stopping a pressurized fluidized bed boiler and a gas turbine in a steam turbine / gas turbine combined plant having a pressurized fluidized bed boiler. In FIG. 2, 38 is a pressurized fluidized bed boiler, 36 is a gas turbine driven by the combustion gas of the pressurized fluidized bed boiler 38, 34 is a compressor driven by the gas turbine 36, and 35 is for the gas turbine 36. It is an auxiliary combustor. Reference numerals 31, 32 and 33 are cutoff valves, and 37 is a bypass valve.

In the thus constructed plant of FIG. 2, the shut-off valves 31 and 32 are closed and the shut-off valve 33 is opened to start the compressed air of the compressor 34 at the auxiliary combustor 35 when the plant is started.
The gas turbine 36 is driven by burning fuel such as gas fuel or liquid fuel.

In FIG. 2, among the valves 31 to 33, 37, the white ones are open and the black ones are closed, and the state of FIG. 2 shows the valve open / closed state during operation. on the other hand,
At the time of a plant trip, the shutoff valves 31 and 32 are closed, the bypass valve 37 and the shutoff valve 33 are opened to guide the discharge air of the air compressor 34 to the gas turbine 36, and the combustion gas in the pressurized fluidized bed boiler 38 and the pipe is chimney. Bypass each to 39.

In a complex plant having a pressurized fluidized bed boiler, a safety device and some valves for starting the pressurized fluidized bed boiler are required to safely stop the gas turbine. These valves are the safety devices. Therefore, high reliability is required, performance requirements such as minimizing pressure loss during normal operation are also required, and the function as a control valve must be exerted at the time of startup.

[0006]

DISCLOSURE OF THE INVENTION The present invention is capable of exhibiting various highly reliable required functions as described above, and in particular, a valve for smoothly starting and stopping a gas turbine and a pressurized fluidized bed boiler. It is an object to provide a combined plant having a system.

[0007]

The present invention relates to a pressurized fluidized bed boiler, a gas turbine driven by combustion gas from the boiler, and a combined plant having a compressor driven by the gas turbine. To solve the problem, the following configuration is adopted.

That is, the compressor outlet of the three-way valve structure is provided in the outlet pipe of the compressor, one of which is connected to the pressurized fluidized-bed boiler and the other is connected to the starting combustor connected to the gas inlet pipe of the gas turbine. A valve, a high temperature gas cutoff valve provided in a pipe connecting the pressurized fluidized bed boiler and the starting combustor,
And a conduit provided between the outlet pipe of the compressor upstream of the compressor outlet valve and the pressurized fluidized bed boiler and having a purge booster valve, and between the upstream side and the start-up combustor. And a conduit provided with a compressor outlet bypass valve. The combined plant configured in this way can be started by the following procedure.

(1) Single start of the gas turbine. In order to start the boiler, it is necessary to raise the pressure and raise the temperature of the boiler. In order to use the gas turbine for boosting the boiler, it is necessary to start the gas turbine first. Therefore, after accelerating the gas turbine, fuel is burned in the combustor for starting the gas turbine, the combustion gas is guided to the gas turbine, and the gas turbine alone starts operation. For this purpose, it is necessary to connect the gas turbine compressor, the pressurized fluidized bed boiler, and the startup combustor, respectively, and switch the flow of compressed air between startup and normal operation.

In the combined plant according to the present invention,
A compressor outlet valve having a three-way valve structure is installed at the compressor outlet, and by providing this three-way valve, the compressed air flow passage is not blocked, so that the occurrence of surging due to the blockage of the flow passage can be avoided. Further, during startup of the gas turbine, it is also necessary to isolate the start-up combustor and the pressurized fluidized bed boiler. Therefore, in the present invention, a high temperature gas is provided in the pipeline connecting the start-up combustor and the pressurized fluidized bed boiler. A shutoff valve is installed.

(2) Startup of the pressurized fluidized bed boiler. In order to activate the pressurized fluidized bed boiler, it is necessary to raise the pressure of the pressurized fluidized bed boiler and raise the temperature of the pressurized fluidized bed boiler before charging the fuel coal. The pressure of the pressurized fluidized bed boiler is raised by the gas turbine compressor, and the temperature is raised by the temperature raising device in the pressurized fluidized bed boiler. for that reason,
After the gas turbine is operated independently, the compressor outlet valve is controlled to send a part of the compressed air to the pressurized fluidized bed boiler side to increase the pressure in the pressurized fluidized bed boiler.

After the pressurization is completed, the temperature rising device in the pressurized fluidized bed boiler raises the temperature of the pressurized fluidized bed boiler and opens the high temperature gas cutoff valve to guide the combustion gas from the pressurized fluidized bed boiler to the gas turbine.
Until the gas turbine inlet gas temperature stabilizes even after the high temperature gas cutoff valve is opened, the compressor outlet valve is controlled to send a portion of the discharge air to the combustor for start-up and burn it to the gas turbine. To control.

When the pressurized fluidized bed boiler is started, the compressor outlet valve controls the flow distribution to the pressurized fluidized bed boiler side and the starting combustor side, but the pressurized fluidized bed boiler is fully opened only by the compressor outlet valve. In the region near the fully closed position, the controllability is not proper because the CV value characteristic of the valve is repulsive.

In the combined plant according to the present invention,
Provided between the outlet pipe of the compressor upstream of the compressor outlet valve and the pressurized fluidized bed boiler, and provided with a purge pressure increasing valve, and between the upstream side and the startup combustor. A pipeline having a compressor outlet bypass valve is provided, and the control of the compressor outlet valve can be covered by controlling the opening and closing of these purge booster valve and bypass valve. As described above, the combined plant of the present invention enables smooth and reliable start-up.

Next, in another combined plant of the present invention, the above description is made in a combined plant having a pressurized fluidized bed boiler, a gas turbine driven by combustion gas from the boiler, and a compressor driven by the gas turbine. In addition to the compressor outlet valve of the three-way valve structure and the high temperature gas cutoff valve, a structure is provided which is provided between the outlet pipe of the compressor and the gas inlet pipe of the gas turbine and has a pipeline with a boiler bypass valve. . By using the combined plant having such a configuration, the plant can be smoothly stopped by the following procedure.

(3) Stopping the plant. When shutting down the plant, the gas turbine and the pressurized fluidized bed boiler are isolated and then shut down.
Isolate the gas turbine from the pressurized fluidized bed boiler side and disconnect the generator. Isolation from the pressurized fluidized bed boiler is performed by the compressor outlet valve and high temperature gas cutoff valve. Further, in order to prevent the surging of the gas turbine compressor when the gas turbine is stopped, it is necessary to quickly reduce the pressure at the compressor outlet.

In the combined plant according to the present invention,
As described above, since a pipeline equipped with a boiler bypass valve is provided between the outlet pipe of the compressor and the gas inlet pipe of the gas turbine, at the same time when the gas turbine is stopped, it is separated from the pressurized fluidized bed boiler at the same time. This boiler bypass valve can be opened to prevent surging of the gas turbine compressor.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A combined plant according to the present invention will be specifically described below with reference to an embodiment shown in FIG. FIG. 1 is a valve system diagram around a gas turbine in a combined plant according to an embodiment of the present invention. In the valve system shown in FIG. 1, a compressor outlet pipe 1 is provided with a compressor outlet valve 2 of a three-way valve structure for preventing surging of the compressor, and one of its flow paths is pressurized by a pipe 9 to a fluidized bed. The boiler 3 is connected to the starting combustor 4 by a pipe 12 on the other side.

A high temperature gas cutoff valve 5 is provided in a double manner between the pressurized fluidized bed boiler 3 and the combustor 4 for start-up, so that even if one of them causes a trouble, there is no problem. Has become. Further, a pipe 7 connecting the compressor outlet pipe 1 and the gas turbine gas inlet pipe 6 is provided, and a boiler bypass valve 8 is provided in the pipe 7 to prevent surging of the compressor at the time of load shedding and to perform compression. It is used as a backup in case of trouble with the machine outlet valve 2.

To the pipe 9 from the compressor outlet valve 2 of the compressor outlet pipe 1 to the pressurized fluidized bed boiler 3, a pipe line 10 branched from the upstream side of the compressor outlet valve 2 is connected. Road 1
At 0, a purge pressure increasing valve 11 is provided. Further, a pipe 12 branched from the upstream side of the compressor outlet valve 2 is connected to the pipe 12 extending from the compressor outlet valve 2 to the startup combustor 4, and the pipe 13 has a compressor outlet bypass bypass. A valve 14 is provided. These pipelines 10 and 13 are installed as a backup of the compressor outlet valve 2 at the time of starting the pressurized fluidized bed boiler for the purpose of controlling the air amount.

In addition to the above, the valve system shown in FIG.
Boiler inlet check valve 15 for preventing backflow when the compressor has a trouble, gas turbine bypass valve 16 for releasing pressure of the pressurized fluidized bed boiler 3, load reduction during gas turbine acceleration and load cutoff An air bleed valve 17 for preventing surging and an air blow valve 18 for preventing surging when the gas turbine load is cut off are installed. As described above, in the combined plant according to the present embodiment having the valve system shown in FIG. 1, smooth and reliable start-up and stop can be performed.

[0022]

As described above, the present invention is provided with the three-way valve structure compressor outlet valve, high temperature gas cutoff valve, pipe line equipped with purge booster valve, and pipe line equipped with compressor outlet bypass valve. The combined plant by will enable from gas turbine startup to boiler startup.

Further, when the pressurized fluidized bed boiler is started, it is necessary to carefully control the distribution of the compressed air to the boiler side and the starting combustor side by the compressor outlet valve, and it is not possible to control only the compressor outlet valve. However, according to the combined plant of the present invention, it is possible to perform precise control, and it has a great effect of contributing to the improvement of reliability of the pressurized fluidized bed boiler combined plant.

Further, in the combined plant according to the present invention, which is provided with a pipe line equipped with a compressor outlet valve of a three-way valve structure, a high temperature gas cutoff valve, and a boiler bypass valve, the surging of the compressor at the time of load cutoff is prevented, and First, it is possible to back up when trouble occurs in the compressor outlet valve.

[Brief description of drawings]

FIG. 1 is a valve system diagram around a gas turbine in a combined plant according to an embodiment of the present invention.

FIG. 2 is a system diagram showing an example of a valve system around a gas turbine in a conventional combined plant.

[Explanation of symbols]

 1 Compressor outlet pipe 2 Compressor outlet valve 3 Pressurized fluidized bed boiler 4 Combustor for startup 5 High temperature gas shutoff valve 6 Gas turbine gas inlet pipe 8 Boiler bypass valve 11 Purge boost valve 14 Compressor outlet bypass valve 15 Boiler inlet reverse Stop valve 16 Gas turbine bypass valve 17 Air extraction valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area F02C 9/00 Z

Claims (2)

[Claims] 1. In a combined plant having a pressurized fluidized bed boiler, a gas turbine driven by combustion gas from the boiler, and a compressor driven by the gas turbine, an outlet pipe (1) of the compressor is provided. A compressor outlet valve having a three-way valve structure, one of which is connected to the pressurized fluidized bed boiler (3) and the other of which is connected to a starting combustor (4) connected to a gas inlet pipe (6) of the gas turbine. (2), a high temperature gas cutoff valve (5) provided in a pipe line connecting the pressurized fluidized bed boiler (3) and the start-up combustor (4), and an outlet pipe (1) of the compressor The compressor outlet valve (2)
Between the upstream side and the start-up combustor (4), and a pipe line (10) provided with a purge pressure increasing valve (11) between the upstream side and the pressurized fluidized bed boiler (3). And a pipeline (13) provided at the compressor outlet bypass valve (14). 2. In a combined plant having a pressurized fluidized bed boiler, a gas turbine driven by combustion gas from the boiler, and a compressor driven by the gas turbine, an outlet pipe (1) of the compressor is provided. A compressor outlet valve having a three-way valve structure, one of which is connected to the pressurized fluidized bed boiler (3) and the other of which is connected to a starting combustor (4) connected to a gas inlet pipe (6) of the gas turbine. (2), a high temperature gas cutoff valve (5) provided in a pipe line connecting the pressurized fluidized bed boiler (3) and the start-up combustor (4), and an outlet pipe (1) of the compressor And a gas inlet pipe (6) of the gas turbine, comprising a pipeline (7) having a boiler bypass valve (8).