JP2000213306A - Pressure fluidized bed compound power plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce in-plant power at the stoppage and to improve reliability at the stoppage by providing a means for stopping steaming of condensate at an outlet of a low temperature waste heat recovery heat exchanger and steaming of feed water at an outlet of a high temperature waste heat recovery heat exchanger at the normal plant stopping and emergency stopping. SOLUTION: A high temperature gas discharge pipe 29 having a high temperature gas discharge valve 30 is connected between a high temperature gas pipe 25 at the upstream of a gas turbine inlet valve 26 and a gas turbine outlet pipe 28. By a control device 33 for inputting a signals of a pressure detector 31 a temperature sensor 32 and the like of a pressure fluidized bed boiler pressure vessel 5, at the normal plant stopping, fuel inside a pressure fluidized bed boiler 6 is burned, thereafter an air compressor outlet valve 23 and the gas turbine inlet valve 26 are fully closed, an air supply valve 27 is opened, to isolate a boiler 6 side. Next, the high temperature gas discharge valve 30 is opened, and the high temperature gas is discharged to reduce pressure on the boiler 6 side. Operation of a gas turbine 2 is stopped after completion of pressure reduction of the boiler 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combined pressurized fluidized-bed power plant including a pressurized fluidized-bed boiler, a gas turbine and a steam turbine, and more particularly to an improvement in reliability during a normal stop and an emergency stop of the plant. And means for reducing internal power.

[0002]

2. Description of the Related Art FIG. 8 is a system diagram showing an example of a system configuration of a conventional pressurized fluidized bed combined cycle power plant. In this pressurized fluidized bed combined cycle power plant, an air supply pipe 24 between the air compressor 1 and the pressurized fluidized bed boiler 6 and a hot gas supply pipe 25 between the pressurized fluidized bed boiler 6 and the gas turbine 2 are connected. In addition to installing the boiler bypass pipe 41, a hot gas discharge pipe 29 and a hot gas discharge valve 30 are installed between the junction of the hot gas supply pipe 25 and the boiler bypass pipe 41 and the gas turbine outlet pipe 28. It has been proposed to flow air and hot gas through the boiler bypass pipe 41 and the hot gas discharge pipe 29. Related devices of this type include, for example, JP-A-9-5
0107 and the like.

[0003]

In such a conventional method, since a mixed gas of air and high-temperature gas is discharged to the chimney 10, the system from the gas turbine outlet pipe 28 to the chimney 10 is adapted for high-temperature gas. It must be possible equipment.

In order to cool this mixed gas, it is conceivable to recover the connection of the high-temperature gas exhaust pipe 30 to the inlet side of the high-temperature exhaust heat recovery heat exchanger 8, but about 60% to 100% of the gas is treated. High-temperature exhaust heat recovery unit 8
It is expected that the outlet water supply will flush and steaming will occur, damaging the equipment. In addition, it is necessary to control the pressure for a few seconds at the time of the occurrence of the failure, and it is expected that the control will be very complicated. Further, since the pressure between the air compressor 1 and the pressurized fluidized-bed boiler 6 is maintained at a constant pressure, the high-temperature gas between the pressurized fluidized-bed boiler 6 and the gas turbine 2 is reduced when the gas turbine is stopped. Flows back to the compressor 1,
It is expected that the air compressor 1 will be damaged. Therefore, it is necessary to continuously operate the gas turbine 2 until the gas temperature of the pressurized fluidized-bed boiler 6 and the metal temperature decrease.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent steam condensing at the outlet of the low-temperature exhaust heat recovery heat exchanger and steaming of the feed water at the outlet of the high-temperature exhaust heat recovery heat exchanger at the time of a normal shutdown of the plant and an emergency shutdown. It is an object of the present invention to provide a pressurized fluidized bed combined cycle power plant equipped with a means for improving the performance and reducing the internal power during stoppage.

[0006]

In order to achieve the above object, the present invention provides a pressurized fluidized bed boiler, an air compressor for supplying air to the pressurized fluidized bed boiler, and a hot gas of the pressurized fluidized bed boiler. Including a driven gas turbine and a steam turbine driven by steam from a pressurized fluidized bed boiler, and a generator driven by the gas turbine and the steam turbine, and supplying compressed air from the air compressor to the pressurized fluidized bed boiler In a pressurized fluidized bed combined cycle power plant with a boiler bypass line equipped with an air supply valve that connects an air supply pipe and a hot gas pipe that supplies hot gas from a pressurized fluidized bed boiler to a gas turbine, the plant normally shuts down An air compressor outlet valve that closes at the time of an emergency or emergency stop is provided in the air supply piping, and the gas turbine inlet valve that closes at the time of a plant normal stop or an emergency stop is set at a high level. A high-temperature gas discharge pipe and a high-temperature gas discharge valve that are provided in the gas pipe and open during normal or emergency stop of the plant and discharge air and high-temperature gas from the outlet of the air compressor to the gas turbine inlet to the exhaust gas outlet of the gas turbine. We propose a pressurized fluidized-bed combined cycle power plant equipped with.

The present invention also provides a pressurized fluidized bed boiler, an air compressor for supplying air to the pressurized fluidized bed boiler, a gas turbine driven by hot gas from the pressurized fluidized bed boiler, and a pressurized fluidized bed boiler. An air supply pipe for supplying compressed air from an air compressor to a pressurized fluidized bed boiler, including a steam turbine driven by steam, a gas turbine, and a generator driven by the steam turbine; In an air pressurized fluidized bed combined cycle power plant having a boiler bypass line installed with an air supply valve connecting a high temperature gas pipe for supplying high temperature gas to the A gas turbine inlet valve that is installed in the air supply pipe and closes when the plant is normally stopped or in an emergency stop is installed in the high-temperature gas pipe, and when the plant is normally stopped Alternatively, a hot gas discharge pipe and hot gas discharge valve that open during an emergency stop and discharge air and hot gas from the outlet of the air compressor to the gas turbine inlet to the gas turbine inlet are provided in parallel with the gas turbine inlet valve. We propose a pressurized fluidized bed combined cycle power plant.

In any case, a gas supply pipe and a gas supply valve for supplying nitrogen or air for cooling and diluting the discharged high-temperature gas can be additionally provided.

The present invention further provides a pressurized fluidized bed boiler, an air compressor for supplying air to the pressurized fluidized bed boiler, a gas turbine driven by hot gas from the pressurized fluidized bed boiler, and a pressurized fluidized bed boiler. An air supply pipe for supplying compressed air from an air compressor to a pressurized fluidized bed boiler, including a steam turbine driven by steam, a gas turbine, and a generator driven by the steam turbine; In an air pressurized fluidized bed combined cycle power plant having a boiler bypass line installed with an air supply valve connecting a high temperature gas pipe for supplying high temperature gas to the A gas turbine inlet valve that is installed in the air supply piping and that closes when the plant is normally stopped or when the emergency is stopped is installed in the high-temperature gas piping,
A hot gas exhaust pipe and a hot gas exhaust valve that open during normal or emergency shutdown of the plant and discharge air and hot gas from the air compressor outlet to the gas turbine are provided to the atmosphere to cool and dilute the discharged hot gas. For this purpose, we propose a pressurized fluidized bed combined cycle power plant equipped with a gas supply pipe and a gas supply valve for supplying nitrogen or air.

[0010] In any of the above pressurized fluidized bed combined cycle power plants, the pressure and outlet temperature of the pressurized fluidized bed boiler and the open / close states of the air compressor outlet valve, gas turbine inlet valve, and air supply valve are determined according to the following conditions. An air compressor outlet valve, gas turbine inlet valve, air supply valve, high-temperature gas discharge valve, and a high-temperature gas discharge control device for controlling the opening of the gas supply valve are provided.

This high-temperature gas discharge control device includes a timer for measuring the elapsed time of natural heat radiation after the high-temperature gas discharge valve is fully closed after the pressure reduction from the air compressor to the gas turbine inlet valve is completed. Is also good.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a pressurized fluidized bed combined cycle power plant according to the present invention will be described with reference to FIGS.

Embodiment 1 FIG. 1 is a system diagram showing a configuration of an embodiment 1 of a combined pressurized fluidized-bed power plant according to the present invention. The air compressor 1 including the starting motor 4 compresses the air sucked from the air inlet valve 22, and compresses the compressed air via the air compressor outlet valve 23 and the air supply pipe 24 into a pressurized fluidized bed boiler pressure vessel. The feed is supplied to the pressurized fluidized-bed boiler 6 in 5. The high-pressure gas from the pressurized fluidized-bed boiler 6 is supplied to a high-temperature gas pipe 25, a high-temperature gas dust remover 7, and a gas turbine inlet valve 26.
Is supplied to the gas turbine 2 via the
And the gas turbine generator 3 converts the energy into electric power. The high-pressure gas that has worked in the gas turbine 2 passes through the gas turbine outlet pipe 28, the high-temperature exhaust heat recovery heat exchanger 8, and the low-temperature exhaust heat recovery heat exchanger 9, and is discharged from the chimney 10 to the atmosphere.

On the other hand, the water heated by the pressurized fluidized-bed boiler 6 becomes only steam by the steam separator 21 and is guided to the high-pressure turbine 11 by the main steam pipe 34. The steam that has worked in the high-pressure turbine 11 is returned to the pressurized fluidized-bed boiler 6 in the low-temperature reheat steam pipe 35, reheated, and guided to the medium-pressure turbine 12 in the high-temperature reheat steam pipe 36. The steam that has worked in the medium pressure turbine 12 is led to the low pressure turbine 13. The high-pressure turbine 11, the intermediate-pressure turbine 12, and the low-pressure turbine 13 are provided with coaxial steam turbine generators 14, which convert steam energy into electric power. The steam that has passed through the low-pressure turbine 13 is cooled by the condenser 15,
It is condensed. The condensed water is pressurized by a condensate pump 16, passes through a low-pressure feed water heater 17, the low-temperature exhaust heat recovery heat exchanger 9, and is deaerated by a deaerator 18. Further, it is pressurized by the feed water pump 19, passes through the high pressure feed water heater 20, the high temperature exhaust heat recovery heat exchanger 8, and is supplied again to the pressurized fluidized bed boiler 6 in the pressurized fluidized bed boiler pressure vessel 5. You.
The brackish water separator 21 has a brackish water separator level control valve 37.
Is connected to the condenser 15 by a pipe having

A bypass pipe provided with an air supply valve 27 is connected between the outlet of the air compressor 1 and the inlet of the gas turbine 2. Further, a pressurized fluidized-bed boiler pressure vessel pressure detector 31 is attached to the pressurized fluidized-bed boiler pressure vessel 5, and a pressurized fluidized-bed boiler temperature detector 32 is attached to the high-temperature gas pipe 25.

In the first embodiment, a high-temperature gas discharge pipe 29 having a high-temperature gas discharge valve 30 is provided between the high-temperature gas pipe 25 upstream of the gas turbine inlet valve 26 and the gas turbine outlet pipe 28. Connected.

The hot gas discharge control device 33 which takes in signals from at least the pressure vessel pressure detector 31 of the pressurized fluidized-bed boiler pressure sensor 31 and the pressurized fluidized-bed boiler temperature detector 32, etc. 23, the opening and closing of the gas turbine inlet valve 26, the air supply valve 27, and the high temperature gas discharge valve 30 are controlled.

In the first embodiment, during normal operation, air taken into the air compressor 1 from the air compressor inlet valve 22 is supplied to the pressurized fluidized bed in the pressurized fluidized bed boiler pressure vessel 5 by the air supply pipe 24. It is led to the boiler 6. The high-temperature gas from the pressurized fluidized-bed boiler 6 is guided to the high-temperature gas dust remover 7 by the high-temperature gas pipe 25 to remove ash and the like, and then supplied to the gas turbine 2 by the high-temperature gas pipe 25 to generate a gas turbine generator. 3 to generate electricity. Exhaust gas from the gas turbine 2 is led to a high-temperature exhaust heat recovery heat exchanger 8 and a low-temperature exhaust heat recovery heat exchanger 9 by a gas turbine outlet pipe 28, and is recovered by a steam turbine system. Released.

On the other hand, the steam generated by the pressurized fluidized bed boiler 6 is supplied to the main steam pipe 34, the high pressure turbine 11, the low temperature reheat steam pipe 35, the pressurized fluidized bed boiler 6, the high temperature reheat steam pipe 3
6, while passing through the medium pressure turbine 12 and the low pressure turbine 13 and reaching the condenser 15, the steam turbine generator 14 is driven to generate power. The water cooled and condensed by the condenser 15 to become condensed water is pressurized by the condensate pump 16 and is supplied to the low pressure feed water heater 1.
7 and the low-temperature exhaust heat recovery heat exchanger 9,
8 is supplied. The feedwater supplied to the deaerator 18 is further pressurized by a feedwater pump 19, heated by a high-pressure feedwater heater 20 and a high-temperature exhaust heat recovery heat exchanger 8, and then supplied again to the pressurized fluidized-bed boiler 6. You.

When the plant is normally stopped, after the fuel in the pressurized fluidized bed boiler 6 is burned, the air compressor outlet valve 23 and the gas turbine inlet valve 26 are fully closed and the air supply valve 27 is opened. The pressure fluidized bed boiler 6 side is in an isolated state.
On the other hand, the gas turbine 2 is operated by the starting motor 4 with the rotation speed of the gas turbine 2 lowered to 10%. At this time, the system on the pressurized fluidized-bed boiler 6 side opens the high-temperature gas discharge valve 30 of the high-temperature gas discharge pipe 29, discharges the high-temperature gas to the gas turbine outlet pipe 28, and outputs the high-temperature exhaust heat recovery heat exchanger 8 and the low-temperature The heat is recovered in the steam turbine system by the exhaust heat recovery heat exchanger 9 and exhausted from the chimney 10 to the atmosphere.
Reduce pressure. When the decompression of the pressurized fluidized-bed boiler 6 is completed,
The gas turbine 2 is stopped or turned slowly.

In this case, in order to prevent the hot gas from flowing back to the air compressor 1, the amount of discharge from the high-temperature gas discharge valve 30 is determined by the difference between the leak amount of the gas turbine inlet valve 26 and the high-temperature gas discharge amount. Air compressor 1 whose total number of rotations is 10%
And the draft volume of the chimney 10 must be equal to or less than the total value. The hot gas discharge control device 33 controls the amount of hot gas discharge according to the signal from the pressurized fluidized bed boiler pressure vessel pressure detector 31 and the signal from the pressurized fluidized bed boiler outlet temperature detector 32, The high-temperature gas discharge amount is controlled so that the total value of the leak amount and the high-temperature gas discharge amount of the turbine inlet valve 26 is equal to or less than the total value of the air flow amount of the air compressor 1 and the draft amount of the chimney 10 whose rotation speed is 10%. Further, the discharge temperature from the high-temperature gas discharge valve 30 is controlled within the equipment plan value at the gas turbine outlet according to the signal from the temperature detector 32 of the pressurized fluidized-bed boiler 6.

On the other hand, in the steam turbine system, the amount of steam generated by the pressurized fluidized bed boiler 6 decreases, and the water level of the steam separator 21 rises.
The condensate is sufficiently collected in the condenser 15. The feedwater collected in the condenser 15 is cooled by the condenser 15, pressurized by the condenser pump 16, and sent to the deaerator 18 via the low-pressure feedwater heater 17 and the low-temperature exhaust heat recovery heat exchanger 9. Supplied. The pressure of the feed water supplied to the deaerator 18 is increased by a feed water pump 19 and raised by a high-pressure feed water heater 20 and a high-temperature exhaust heat recovery heat exchanger 8, and then the steam separator 21 and the brackish water separator level control valve 37. Is supplied to the condenser 15 through the above-mentioned state, and enters a circulating operation state.

As a result, the high-temperature gas at the time of decompression on the side of the pressurized fluidized-bed boiler 6 is recovered by the low-temperature exhaust heat recovery heat exchanger 9 and the high-temperature exhaust heat recovery heat exchanger 8 as condensate water and feed water, and condensed. Vessel 1
By means of 5, the recovered heat can be cooled.

In particular, the amount of high-temperature gas at the time of decompression on the pressurized fluidized-bed boiler 6 side includes the air volume of the air compressor 1 having a rotation speed of 10%, the draft air volume of the chimney 1, the high-temperature gas discharge volume, and the gas turbine inlet valve 26. However, since it is very small compared to the gas amount during normal operation, the steaming of the condensed water at the outlet of the low-temperature exhaust heat recovery heat exchanger 9 and the supply of the water at the outlet of the high-temperature exhaust heat recovery heat exchanger 8 are performed. Steaming can be prevented.

Further, when the condensing pump 16 and the feed water pump 19 are operable and the water supply can be supplied to the high-temperature exhaust heat recovery heat exchanger 9 and the low-temperature exhaust heat recovery heat exchanger 9 in an emergency stop, the pressurized flow is stopped. The high-temperature gas at the time of decompression on the floor boiler 6 side is recovered by the low-temperature exhaust heat recovery heat exchanger 9 and the high-temperature exhaust heat recovery heat exchanger 8 into condensed water and feedwater, and the recovered heat can be cooled by the condenser 15 The operation can be performed in the same manner as the normal stop of the plant.

Embodiment 2 FIG. 2 is a system diagram showing the configuration of Embodiment 2 of a combined pressurized fluidized-bed power plant according to the present invention. In the second embodiment, instead of the gas turbine outlet pipe 28, the hot gas pipe 25 upstream of the air supply valve 27,
This embodiment is different from the first embodiment in that a high-temperature gas discharge pipe 29 having a high-temperature gas discharge valve 30 is connected and a gas turbine inlet valve 26 is bypassed.

In the second embodiment, when the plant is normally stopped, the fuel in the pressurized fluidized-bed boiler 6 is burned, then the air compressor outlet valve 23 and the gas turbine inlet valve 26 are fully closed, and the air supply valve 27 is closed. Is opened, the pressurized fluidized-bed boiler 6 side is in an isolated state. On the other hand, the gas turbine 2 is operated by the starting motor 4 with the rotation speed of the gas turbine 2 lowered to 10%. At that time, the system on the pressurized fluidized-bed boiler 6 side opens the high-temperature gas discharge valve 30 of the high-temperature gas discharge pipe 29, discharges the high-temperature gas to the inlet of the gas turbine 2, passes through the gas turbine 2, and discharges the high-temperature gas. The heat is recovered to the steam turbine system by the heat recovery heat exchanger 8 and the low-temperature exhaust heat recovery heat exchanger 9, exhausted to the atmosphere from the chimney 10, and depressurized. When the depressurization on the pressurized fluidized-bed boiler 6 side is completed, the gas turbine 2 is stopped or turned at a low speed.

In the second embodiment, since the operation can be performed in the same manner as in the first embodiment, the steaming of the condensed water at the outlet of the low-temperature exhaust heat recovery heat exchanger 9 and the steaming of the feedwater at the outlet of the high-temperature exhaust heat recovery heat exchanger 8 can be performed. , The reliability of the plant can be improved at the time of a normal stop of the plant and at the time of an emergency stop, and the internal power at the time of the stop can be reduced.

Third Embodiment FIG. 3 is a system diagram showing a configuration of a third embodiment of a combined pressurized fluidized-bed power plant according to the present invention. In the third embodiment, a hot gas discharge pipe 29 having a hot gas discharge valve 30 is used instead of the gas turbine outlet pipe 28.
The first embodiment is different from the first embodiment in that a gas supply pipe 39 provided with a gas supply valve 38 is provided in addition to a gas supply valve 38 connected to the atmosphere.

In the third embodiment, when the plant is normally stopped, after the fuel in the pressurized fluidized bed boiler 6 is burned, the air compressor outlet valve 23 and the gas turbine inlet valve 26 are fully closed, and the air supply valve 27 is closed. Is opened, the pressurized fluidized-bed boiler 6 side is in an isolated state. On the other hand, the gas turbine 2 is operated by the starting motor 4 with the rotation speed of the gas turbine 2 lowered to 10%. At that time, the system on the pressurized fluidized-bed boiler 6 side opens the high-temperature gas discharge valve 30 and the gas supply valve 38 of the high-temperature gas discharge pipe 29, and opens the gas supply pipe 39.
After cooling or diluting the high-temperature gas with the gas from, it is discharged to the atmosphere. When the depressurization on the pressurized fluidized-bed boiler 6 side is completed, the gas turbine 2 is stopped or turned at a low speed.

In this case, the amount of discharge from the high-temperature gas discharge valve 30 is determined by comparing the amount of leakage of the gas turbine inlet valve 26 with the amount of high-temperature gas discharge in order to prevent the high-temperature gas from flowing back to the air compressor 1. Air compressor 1 whose total number of rotations is 10%
And the draft volume of the chimney 10 must be equal to or less than the total value. The hot gas discharge control device 33 controls the amount of hot gas discharge according to the signal from the pressurized fluidized bed boiler pressure vessel pressure detector 31 and the signal from the pressurized fluidized bed boiler outlet temperature detector 32, The high-temperature gas discharge amount is controlled so that the total value of the leak amount and the high-temperature gas discharge amount of the turbine inlet valve 26 is equal to or less than the total value of the air flow amount of the air compressor 1 and the draft amount of the chimney 10 whose rotation speed is 10%. Further, the discharge temperature from the high-temperature gas discharge valve 30 is controlled within the equipment plan value at the gas turbine outlet according to the signal from the temperature detector 32 of the pressurized fluidized-bed boiler 6.

Since the high-temperature gas discharge control device 33 also controls the gas required for cooling and dilution from the gas supply valve 38, that is, nitrogen or air, it dilutes harmful components such as carbon monoxide in the high-temperature gas, Can be released to the atmosphere.

On the other hand, on the gas turbine 2 side, the rotation speed is 10
% Of the air flow of the air compressor 1, the draft air volume of the chimney 10, and the leak amount of the gas turbine inlet valve 26 via the outlets of the low-temperature exhaust heat recovery heat exchanger 9 and the high-temperature exhaust heat recovery heat exchanger 8. And release it from the chimney 10 to the atmosphere. in this case,
Prevents steaming of condensed water at the outlet of the low-temperature exhaust heat recovery heat exchanger 9 and steaming of the feedwater at the outlet of the high-temperature exhaust heat recovery heat exchanger 8 because the gas amount is very small compared to the gas amount during normal operation. it can.

Fourth Embodiment FIG. 4 is a system diagram showing a configuration of a fourth embodiment of a combined pressurized fluidized-bed power plant according to the present invention. In the fourth embodiment, as in the first embodiment, a high-temperature gas discharge pipe 29 having a high-temperature gas discharge valve 30 is provided between a high-temperature gas pipe 25 upstream of the gas turbine inlet valve 26 and a gas turbine outlet pipe 28. After connecting, hot gas exhaust valve 3
Downstream from 0, a gas supply pipe 39 provided with a gas supply valve 38 is also provided.

In the fourth embodiment, when the plant is normally stopped, after fuel in the pressurized fluidized bed boiler 6 is burned, the air compressor outlet valve 23 and the gas turbine inlet valve 26 are fully closed, and the air supply valve 27 is closed. Is opened, the pressurized fluidized-bed boiler 6 side is in an isolated state. On the other hand, the gas turbine 2 is rotated by the starting motor 4 while the rotation speed of the gas turbine 2 is reduced to 10%. At that time, the system on the pressurized fluidized-bed boiler 6 side opens the high-temperature gas discharge valve 30 and the gas supply valve 38 of the high-temperature gas discharge pipe 29, and opens the gas supply pipe 39.
While cooling or diluting the hot gas with the gas from
After the heat is recovered to the steam turbine system by the high-temperature exhaust heat recovery heat exchanger 8 and the low-temperature exhaust heat recovery heat exchanger 9 via the gas turbine outlet pipe 28, the exhaust gas is discharged from the chimney 10 to the atmosphere. When the depressurization on the pressurized fluidized-bed boiler 6 side is completed, the gas turbine 2 is stopped or turned at a low speed.

In this case, in order to prevent the hot gas from flowing back to the air compressor 1, the amount of discharge from the high-temperature gas discharge valve 30 is determined by the difference between the amount of leakage from the gas turbine inlet valve 26 and the amount of high-temperature gas discharge. Air compressor 1 whose total number of rotations is 10%
And the draft volume of the chimney 10 must be equal to or less than the total value. The hot gas discharge control device 33 controls the amount of hot gas discharge according to the signal from the pressurized fluidized bed boiler pressure vessel pressure detector 31 and the signal from the pressurized fluidized bed boiler outlet temperature detector 32, The high-temperature gas discharge amount is controlled so that the total value of the leak amount and the high-temperature gas discharge amount of the turbine inlet valve 26 is equal to or less than the total value of the air flow amount of the air compressor 1 and the draft amount of the chimney 10 whose rotation speed is 10%. Further, the discharge temperature from the high-temperature gas discharge valve 30 is controlled within the equipment plan value at the gas turbine outlet according to the signal from the temperature detector 32 of the pressurized fluidized-bed boiler 6.

Since the high-temperature gas discharge control device 33 also controls the gas required for cooling and dilution from the gas supply valve 38, that is, nitrogen or air, it dilutes harmful components such as carbon monoxide in the high-temperature gas, Can be released to the atmosphere.

On the other hand, on the gas turbine 2 side, the rotation speed is 10
% Of the air flow of the air compressor 1, the draft air volume of the chimney 10, and the leak amount of the gas turbine inlet valve 26 via the outlets of the low-temperature exhaust heat recovery heat exchanger 9 and the high-temperature exhaust heat recovery heat exchanger 8. And release it from the chimney 10 to the atmosphere. in this case,
Prevents steaming of condensed water at the outlet of the low-temperature exhaust heat recovery heat exchanger 9 and steaming of the feedwater at the outlet of the high-temperature exhaust heat recovery heat exchanger 8 because the gas amount is very small compared to the gas amount during normal operation. it can.

The fourth embodiment is an example in which a gas supply pipe 39 having a gas supply valve 38 is provided downstream of the high-temperature gas discharge valve 30 of the first embodiment. It will be clear that a gas supply pipe 39 with a gas supply valve 38 may be provided downstream of the discharge valve 30.

In each of the above embodiments, maintaining the rotation speed of the air compressor 1 at 10% is merely an example, and the present invention is not limited to this value.

FIG. 5 shows a hot gas emission control device 33 in each embodiment of the pressurized fluidized bed combined cycle power plant according to the present invention.
3 is a diagram showing a system configuration of control logic of FIG. The high-temperature gas discharge valve 30 (and the gas supply valve 38) is connected to the gas state value, that is, the detected pressure value 31 of the pressurized fluidized-bed boiler pressure vessel 5 and the detected temperature value 32 of the pressurized fluidized-bed boiler 6, and the air compressor outlet. Valve 23, gas turbine inlet valve 26, air supply valve 27
Is controlled according to the open / closed state of.

In particular, the temperature detection value 3 of the pressurized fluidized bed boiler 6
The control 2 controls the local temperature rise to be avoided even when the high-temperature gas discharge valve 30 is opened and the high-temperature gas flows because the self-combustion temperature of the gas is used as a reference value. That is, even if the unburned gas remains in the high-temperature gas pipe 25 or the equipment, the temperature is set to the self-combustion temperature or lower, so that the temperature rise due to the combustion of the unburned material can be prevented.

Further, after the pressure reduction from the air compressor 1 to the gas turbine inlet valve 26 is completed, the high-temperature gas discharge valve 30
Is fully closed, the gas compressor inlet valve 2
It is conceivable that the pressure between the air compressor 1 and the gas turbine inlet valve 26 rises according to the temperature of the metal up to 6, but a timer is provided for such a phenomenon. When heat is dissipated, it can be cooled sufficiently.

FIG. 6 is a diagram showing a temporal change of the air volume in each embodiment of the pressurized fluidized bed combined cycle power plant according to the present invention. FIG. 7 shows the open / closed state of the valves 23, 26, 27, and 30, the pressure value 31 of the pressurized fluidized-bed boiler pressure vessel 6, and the gas turbine speed in each embodiment of the combined pressurized fluidized-bed power plant according to the present invention. It is a figure showing a relation.

As shown in FIGS. 6 and 7, the air compressor outlet valve 23 and the gas turbine inlet valve 26 are fully closed.
When the air supply valve 27 and the hot gas discharge valve 30 are opened, the pressure of the pressurized fluidized bed boiler 6 decreases, and the number of revolutions of the gas turbine decreases. On the other hand, the air volume is equal to or less than the total value of the air volume from the high-temperature gas discharge valve 30 and the leak amount from the gas turbine inlet valve 26, or equal to or less than the total value of the air volume of the air compressor 1 and the draft amount of the chimney 10. Therefore, the hot gas does not flow back to the air compressor 1 side. The draft amount is
It can be calculated based on the gas temperature at the inlet of the chimney 10 and the atmospheric temperature.

[0046]

According to the present invention, in a pressurized fluidized bed combined cycle power plant comprising a pressurized fluidized bed boiler, a gas turbine and a steam turbine, a low temperature exhaust heat recovery heat exchanger and a high temperature exhaust heat recovery heat exchanger outlet are provided. This prevents water condensing and steaming of the water supply, improves the reliability of the plant during normal stoppage of the plant and emergency stoppage, and reduces the internal power during stoppage.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a configuration of a first embodiment of a combined pressurized fluidized-bed power plant according to the present invention.

FIG. 2 is a system diagram showing a configuration of a second embodiment of a combined pressurized fluidized-bed power plant according to the present invention.

FIG. 3 is a system diagram showing a configuration of a third embodiment of a combined pressurized fluidized-bed power plant according to the present invention.

FIG. 4 is a system diagram showing a configuration of a fourth embodiment of a combined pressurized fluidized-bed power plant according to the present invention.

FIG. 5 is a diagram showing a system configuration of a control logic of a high-temperature gas emission control device in each embodiment of the pressurized fluidized bed combined cycle power plant according to the present invention.

FIG. 6 is a diagram showing a temporal change of air flow in each embodiment of the combined pressurized fluidized bed power plant according to the present invention.

FIG. 7 is a diagram showing a relationship between a valve opening / closing state, a pressurized fluidized-bed boiler pressure vessel side pressure, and a gas turbine speed in each embodiment of the combined pressurized fluidized-bed power generation plant according to the present invention.

FIG. 8 is a system diagram showing an example of a system configuration of a conventional pressurized fluidized bed combined cycle power plant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air compressor 2 Gas turbine 3 Gas turbine generator 4 Starting motor 5 Pressurized fluidized bed boiler pressure vessel 6 Pressurized fluidized bed boiler 7 High temperature gas dust removing device 8 High temperature exhaust heat recovery heat exchanger 9 Low temperature exhaust heat recovery heat exchange Device 10 Chimney 11 High-pressure turbine 12 Medium-pressure turbine 13 Low-pressure turbine 14 Generator for steam turbine 15 Condenser 16 Condensate pump 17 Low-pressure feedwater heater 18 Deaerator 19 Feedwater pump 20 High-pressure feedwater heater 21 Steam separator 22 Air Inlet valve 23 Air compressor outlet valve 24 Air supply pipe 25 High temperature gas pipe 26 Gas turbine inlet valve 27 Air supply valve 28 Gas turbine outlet pipe 29 High temperature gas discharge pipe 30 High temperature gas discharge valve 31 Pressurized fluidized bed boiler pressure vessel pressure detection Vessel 32 pressurized fluidized-bed boiler temperature detector 33 high-temperature gas emission control device 34 main steam pipe 35 low Reheat steam pipe 36 hot reheat steam pipe 37 steam separator level control valve 38 the gas supply valve 39 the gas supply pipe 40 PFBC boiler bypass valve 41 PFBC boiler bypass pipe

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ken Ueno 3-1-1 Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor Nobuyoshi Mishima 3-1-1 Sachimachi, Hitachi-shi, Ibaraki No. 1 F term in Hitachi, Ltd. Hitachi Plant (reference) 3G081 BA02 BA11 BC07 BD00 DA04 DA06 DA21

Claims (6)

[Claims] 1. A pressurized fluidized bed boiler, an air compressor for supplying air to the pressurized fluidized bed boiler, a gas turbine driven by hot gas of the pressurized fluidized bed boiler, and steam of the pressurized fluidized bed boiler And an air supply pipe for supplying compressed air from the air compressor to the pressurized fluidized-bed boiler, and the pressurized fluidized-bed boiler, comprising: a steam turbine driven by an air compressor; and a generator driven by the gas turbine and the steam turbine. An air pressurized fluidized bed combined cycle power plant having a boiler bypass line provided with an air supply valve for connecting a high temperature gas pipe for supplying a high temperature gas to the gas turbine from above A gas outlet valve is provided in the air supply pipe, and a gas turbine inlet valve that closes during a normal stop or an emergency stop of the plant is connected to the high-temperature gas pipe. A high-temperature gas discharge pipe and a high-temperature gas discharge valve that are opened during normal or emergency stop of a plant and discharge air and high-temperature gas from an outlet of the air compressor to an inlet of the gas turbine to an exhaust gas outlet of the gas turbine. And a combined pressurized fluidized bed power plant. 2. A pressurized fluidized bed boiler, an air compressor for supplying air to the pressurized fluidized bed boiler, a gas turbine driven by hot gas of the pressurized fluidized bed boiler, and steam of the pressurized fluidized bed boiler And an air supply pipe for supplying compressed air from the air compressor to the pressurized fluidized-bed boiler, and the pressurized fluidized-bed boiler, comprising: a steam turbine driven by an air compressor; and a generator driven by the gas turbine and the steam turbine. An air pressurized fluidized bed combined cycle power plant having a boiler bypass line provided with an air supply valve for connecting a high temperature gas pipe for supplying a high temperature gas to the gas turbine from above A gas outlet valve is provided in the air supply pipe, and a gas turbine inlet valve that closes during a normal stop or an emergency stop of the plant is connected to the high-temperature gas pipe. A high-temperature gas discharge pipe and a high-temperature gas discharge valve which are opened at the time of a plant normal stop or an emergency stop to discharge air and a high-temperature gas from an outlet of the air compressor to an inlet of the gas turbine to an inlet of the gas turbine. A combined pressurized fluidized-bed power generation plant, which is provided in parallel with the gas turbine inlet valve. 3. The pressurized fluidized bed combined cycle power plant according to claim 1, further comprising a gas supply pipe and a gas supply valve for supplying nitrogen or air for cooling and diluting the discharged hot gas. A combined pressurized fluidized-bed power plant characterized by the following. 4. A pressurized fluidized bed boiler, an air compressor for supplying air to the pressurized fluidized bed boiler, a gas turbine driven by hot gas of the pressurized fluidized bed boiler, and steam of the pressurized fluidized bed boiler And an air supply pipe for supplying compressed air from the air compressor to the pressurized fluidized-bed boiler, and the pressurized fluidized-bed boiler, comprising: a steam turbine driven by an air compressor; and a generator driven by the gas turbine and the steam turbine. An air pressurized fluidized bed combined cycle power plant having a boiler bypass line provided with an air supply valve for connecting a high temperature gas pipe for supplying a high temperature gas to the gas turbine from above A gas outlet valve is provided in the air supply pipe, and a gas turbine inlet valve that closes during a normal stop or an emergency stop of the plant is connected to the high-temperature gas pipe. Provided with a high-temperature gas discharge pipe and a high-temperature gas discharge valve that open during normal or emergency stop of the plant and discharge air and high-temperature gas from the air compressor outlet to the gas turbine to the atmosphere, and cool the discharged high-temperature gas A combined pressurized fluidized-bed power plant comprising a gas supply pipe and a gas supply valve for supplying nitrogen or air for dilution. 5. The pressurized fluidized bed combined cycle power plant according to claim 1, wherein a pressure and an outlet temperature of the pressurized fluidized bed boiler, the air compressor outlet valve, and the gas turbine are provided. A high temperature for controlling the opening of the air compressor outlet valve, the gas turbine inlet valve, the air supply valve, the high-temperature gas discharge valve, and the gas supply valve according to the open / close state of the inlet valve and the air supply valve. A combined pressurized fluidized-bed power plant comprising a gas emission control device. 6. The pressurized fluidized-bed combined cycle power plant according to claim 5, wherein the high-temperature gas discharge control device discharges the high-temperature gas after completing the pressure reduction from the air compressor to the gas turbine inlet valve. A pressurized fluidized bed combined cycle power plant comprising a timer for measuring an elapsed time of natural heat release after the valve is fully closed.