JPH07158819A - Compressor surge protection device - Google Patents

Abstract

PURPOSE:To enable a variation rate of a temperature of gas at a gas turbine inlet to be prevented from exceeding a possibility of its limitation when air is flowed through a bypassing line by a method wherein an amount of air flowing through the bypass line is adjusted. CONSTITUTION:In the case that an actual pressure ratio of a compressor is more than a value near a surge region, an output signal of a constant number generator 15 of outputs of a changing-over switch 16 is inputted to a control device 07 by a changing-over switch 19. A signal to cause a valve to perform its opening operation within a range not exceeding a limitation of an upper/ lower limiter 08 is outputted as a gas turbine valve opening degree instruction 09. At this time, the air pressurized by a compressor passes through the bypass line and is discharged to the gas turbine. In the case that a variation rate of temperature of gas at a gas turbine inlet port exceeds its limitation while exceeding a value more than the surge region, an output signal of the constant number generator 18 is selected by the changing-over switch 19. At this time, the gas turbine valve opening degree instruction 09 is kept at its present opening degree, an amount of bypassing air becomes constant and its temperature is stabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a protective device for automatically preventing operation of a compressor for supplying combustion air to a pressurized fluidized bed boiler or the like in a surge region.

[0002]

2. Description of the Related Art A compressor / surge protective device (application number: Japanese Patent Application No. 4-2565) which has not been published by the present inventors.
No. 17) is shown in FIG. In FIG. 2, 30 is a pressurized fluidized bed boiler, and 32 is a compressor for sending compressed air to the pressurized fluidized bed boiler 30. The air passing through the compressor vane valve 31 is compressed by the compressor 32, flows into the pressure vessel 33, and becomes exhaust gas in the combustion furnace 34 and flows into the gas turbine. A valve 37 for controlling the bypass air flow rate is installed in the air bypass line 36 for protecting the compressor / surge.
Normally, the valve 37 is closed. When the actual pressure ratio of the compressor is in the vicinity of the surge region or more, the valve 37 is opened. At this time, since air flows from the compressor 32 into the gas turbine 35, the pressure ratio of the compressor 32 decreases and the surge region shifts to the normal operation region.

Next, FIG. 3 shows a block diagram of a control circuit of the invention which has not been disclosed in the above-mentioned prior application. The function generator 42 which receives the measured compressor passage air flow rate 41 outputs the surge pressure ratio of the compressor. Further, the measured compressor actual pressure ratio 43 and the output signal 44 of the constant generator are added by the adder 45. The signal of the constant generator 44 is a safety factor for preventing the surge area entry. The output signal of the adder 45 is subtracted from the output signal of the function generator 42 by the subtractor 46, and takes a positive value in the vicinity of the surge line or above, and outputs a signal for opening the valve 37.

Controller (eg, PI controller) 47
Takes the output signal of the subtractor 46 as an input. The output signal of the controller 47 becomes the input signal of the upper / lower limit limiter 48,
The output signal of the upper / lower limit limiter serves as the gas turbine bypass air valve opening command 49 to prevent the surge region from entering.

[0005]

SUMMARY OF THE INVENTION The compressor / surge protection device of the above-mentioned invention filed by the present inventors has an air bypass line, and when the actual pressure ratio of the compressor is in the vicinity of the surge region or more, the compressor The compressed air flows into the gas turbine inlet through the bypass line. The gas turbine inlet gas temperature during normal operation is 600 ° C to 830 ° C, whereas the compressed air is 220 ° C to 350 ° C. Since it was low, there was a possibility that the rate of change in the gas temperature at the gas turbine inlet would be exceeded.

The present invention has been made in order to solve the problems of the above-mentioned invention of the above-mentioned application, and there is a possibility that the rate of change of the gas temperature at the gas turbine inlet is exceeded when air is introduced through the bypass line. The purpose is to eliminate.

[0007]

In order to achieve the above object, the present invention supplies air pressurized by a compressor through a pressure vessel to a fluidized bed combustion furnace for combustion under pressurized air. In a plant that supplies combustion gas generated in a fluidized bed combustion furnace to a gas turbine, a bypass line for introducing air compressed by the compressor into the gas turbine, a valve installed in the bypass line, and an actual pressure of the compressor When the ratio is in the vicinity of the surge region or more, a control circuit for performing the opening operation of the valve and the inlet gas temperature of the gas turbine are detected, and when the rate of change of the inlet gas temperature exceeds a certain range, the opening degree of the valve is adjusted. The present invention provides a compressor / surge protector for a pressurized fluidized bed boiler, which is provided with a control circuit for maintaining it constant.

[0008]

According to the present invention, the pressure ratio of the compressor prevents the surge area from entering the surge region by allowing the air to flow in through the bypass line, and the amount of the air flowing in through the bypass line is adjusted. The change rate of the inlet gas temperature can be limited, and the operation that protects the gas turbine can be performed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the compressor / surge protection device of the present invention will be explained based on the control block diagram of the present invention shown in FIG. The function generator 02 which receives the measured compressor passage air flow rate 01 outputs the surge pressure ratio of the compressor. Further, the measured compressor actual pressure ratio 03 and the safety factor for preventing the surge area rush which is the output signal of the constant generator 04 are added by the adder 05. The subtractor 06 subtracts the compressor surge pressure ratio calculated by the function generator 02 from the sum of the compressor actual pressure ratio added by the adder 05 and the safety coefficient, but has a positive value near the surge line. . Switch 1
6 selects the output signal of the negative constant generator 17 when the output signal of the subtractor 06 is negative, and selects the output signal of the positive constant generator 15 when the output signal of the subtractor 06 is positive. select.

On the other hand, the temperature change rate limiting circuit for the gas temperature at the gas turbine inlet has the following configuration. The measured gas turbine inlet gas temperature 10 is the primary delay element 1
1 input signal. In order to obtain the temperature changed per unit time at that time, the output signal of the primary delay element 11 is subtracted from the gas turbine inlet gas temperature 10 by the subtractor 12. The subtractor 14 subtracts the output signal of the subtractor 12 from the limit value of the temperature change rate output from the constant generator 13.

The changeover switch 19 outputs the output signal of the changeover switch 16 when the output signal of the subtractor 14 is positive (that is, when it falls within the gas turbine inlet gas temperature change rate limit), and when it is negative ( That is, when the gas turbine inlet gas temperature change rate exceeds the limit), the output signal of the constant generator 18 is input to the controller 07.

Normally, the output signal of the changeover switch 16 is selected by the changeover switch 19, and the changeover switch 16 is selected.
The output signal of the constant generator 17 is input to the controller 07. In this case, the gas turbine valve opening command 0
Since 9 is a signal that causes the valve to close in a range that does not touch the upper / lower limit limiter 08, the gas turbine bypass air valve is eventually closed.

When the actual pressure ratio of the compressor is above the surge region, the changeover switch 19 is used to change the changeover switch 1
The output signal of 6 is selected, and the output signal of the constant generator 15 of the outputs of the changeover switch 16 is input to the controller 07. Then, a signal for opening the valve is output as a gas turbine valve opening degree command 09 within a range not touching the limit of the upper / lower limit limiter 08. At this time, the air compressed by the compressor is discharged to the gas turbine through the bypass line. The amount of air released gradually increases as the valve opens little by little, so that a sufficient amount of air is eventually bypassed to prevent surge area entry.

The gas turbine valve opening command 09 is a signal for opening the valve, but when it is still in the vicinity of the surge region or more and the gas turbine inlet gas temperature change rate exceeds the limit,
The changeover switch 19 selects the output signal of the constant generator 18. At this time, the gas turbine valve opening degree command 09 is maintained at the current opening degree. Then, the amount of air bypassed to the gas turbine becomes constant and the temperature stabilizes, so that the gas turbine inlet gas temperature change rate falls within the limit again.

After that, when the actual pressure ratio of the compressor leaves the vicinity of the surge region, the output of the changeover switch 16 is selected again by the changeover switch 19, and the output signal of the constant generator 17 among the outputs of the changeover switch 16 is the controller. It is input to 07. Then, a signal for closing the valve is output as the gas turbine valve opening degree command 09 within a range not touching the control of the upper / lower limit limiter 08.

By performing the above control, it is possible to prevent the surge region from entering the compressor, and it is possible to operate the plan without touching the limit of the temperature change rate of the gas turbine inlet gas.

[0017]

The compressor / surge protector according to the present invention can prevent the surge area from entering during operation and improve the safety of the plant without touching the limit of the rate of change of the gas turbine inlet temperature.

[0018]

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a compressor / surge protection device according to the present invention.

FIG. 2 is an invention filed by the present inventor (Japanese Patent Application No. 04-2565).
17) Compressor / surge protector configuration diagram

FIG. 3 is a block diagram of a compressor / surge protection device of the present invention already filed by the present inventor.

[Explanation of symbols]

01,41 Compressor passing air flow rate (measurement data) 02,42 Function generator 03,43 Compressor pressure ratio (measurement data) 04,13,15 Constant generator 17,18,44 Constant generator 05,45 Adder 06, 12, 14, 46 Subtractor 07, 47 Controller (for example, PI controller) 08, 48 Upper / lower limit limiter 09, 49 Gas turbine bypass air valve opening command 10 Gas turbine inlet gas temperature 11 Primary delay element 16, 19 Switching Switch 31 Variable compressor vane valve 32 Compressor 33 Pressure vessel 34 Combustion furnace 35 Gas turbine 36 Bypass air line 37 Gas turbine bypass air valve

Claims (1)

[Claims] 1. Air compressed by a compressor is supplied through a pressure vessel to a fluidized bed combustion furnace that burns under compressed air.
In a plant that supplies combustion gas generated in the fluidized bed combustion furnace to a gas turbine, a bypass line that allows the air pressurized by the compressor to flow into the gas turbine, a valve installed in the bypass line, and an actual compressor of the compressor. A control circuit that opens the valve when the pressure ratio is in the vicinity of the surge region and above, and the opening of the valve when the inlet gas temperature of the gas turbine is detected and the rate of change of the inlet gas temperature exceeds a certain range. A compressor / surge protector for a pressurized fluidized bed boiler, which is provided with a control circuit for maintaining a constant value.