JPH08285202A - Fluidized bed boiler generating plant - Google Patents

Abstract

PURPOSE: To eliminate a need for cold blowoff during black out of a generating plant and to perform restarting in the same given time as in the ordinary stop of a boiler even during the emergency stop of a boiler. CONSTITUTION: When a fluidized bed boiler 1 is stopped, steam from the fluidized bed boiler 1 is introduced to a feed-water-pump drive turbine 11, and a feed water pump 10 and feed water booster pump 9 are driven. Further, steam from the fluidized bed boiler 1 is introduced to a turbine 11 for emergency to drive a generator 5 for emergency coupled to the turbine 11 for emergency. The generating power of the generator 5 for emergency is fed as a drive source to a condensate pump 10 and a condensate booster pump 9. Thus, even when the fluidized bed boiler 1 is stopped, feed of water can be continued.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed boiler power plant using a fluidized bed boiler having a large amount of residual heat.

[0002]

2. Description of the Related Art In recent years, as one of the main power generation systems for future coal-fired power plants, a fluidized bed power plant which can achieve high efficiency and low pollution and can realize low cost has been attracting attention.

This fluidized bed boiler can be classified into a normal pressure fluidized bed combustion boiler that burns the interior of the furnace at atmospheric pressure and a pressurized fluidized bed boiler that burns the interior of the furnace in a pressurized state. It can be classified into four types: circulating fluidized bed boiler that recirculates the inside of the furnace, and boiling fluidized bed boiler that suppresses the flow velocity of pulverized coal in the furnace by using an indirect heat medium such as coal (hereinafter referred to as bed material) inside the furnace. . Here, the circulating fluidized bed boiler and the boiling fluidized bed boiler are intended to increase the combustion efficiency of coal and the efficiency of heat transfer to feed water.

In such a fluidized bed boiler, since the fuel is contained in the furnace in a layered form of several mm to several tens of mm, the residual heat quantity of the fuel left in the boiler even after the fuel input is stopped. Is very large, and in the boiling fluidized bed boiler, the heat medium itself also possesses a considerable amount of heat. Therefore, in order to prevent the boiler tube from being damaged by the residual heat of the boiler even after the operation of the boiler is stopped, it is necessary to keep the water supply from the turbine system to the boiler uninterrupted.

[0005]

However, since various pumps for supplying water from the turbine system to the boiler are often driven by a motor as described above, when the power plant is completely shut down or a system external power source is used. In the event of an accident, the power supply for the pump drive will be cut off. If the pump cannot be driven, the water supply to the boiler will be cut off, and the boiler tube will be damaged by the amount of residual heat in the boiler.

Further, when cold blow-off is performed, the fuel becomes ash mixed with water in the furnace of the boiler, and the ash cannot be restarted unless the ash is removed. Further, in a boiling fluidized bed boiler using a bed material, there is a problem that the bed material itself fits with water and solidifies into concrete. Once cold blow off, the time required to restart the power plant is about 24 hours to remove ash in the circulating fluidized bed boiler, and the solidified bed material is removed in the boiling fluidized bed boiler. It takes about one month and takes a lot of time. Therefore,
During the period required for restoration, the power plant cannot generate power, which may hinder stable power supply.

An object of the present invention is to provide a fluidized bed boiler power generation plant which makes cold blow-off unnecessary when the power plant is completely shut down and can be restarted in the same required time as a normal boiler stoppage even in the case of an emergency stop of the boiler. Is to get.

[0008]

According to a first aspect of the present invention, when a fluidized bed boiler is stopped, steam from the fluidized bed boiler is introduced into a feed water pump and a feed water pump driving turbine that drives a feed water booster pump. And an emergency turbine driven by steam from the fluidized bed boiler when the fluidized bed boiler stops, and an emergency generator for supplying power for driving the condensate pump and the condensate booster pump. It is connected to the turbine.

According to a second aspect of the present invention, a steam line is provided for introducing steam from the fluidized bed boiler to a feed water pump and a feed water pump driving turbine for driving the feed water booster pump when the fluidized bed boiler is stopped. Also, an emergency generator for supplying power for driving the condensate booster pump is connected to the feed water pump drive turbine.

According to a third aspect of the present invention, the emergency generator according to the second aspect is connected to a feed water pump driving turbine via a fluid coupling.

According to the invention of claim 4, a makeup water tank for storing makeup water for supplying water to the fluidized bed boiler is provided, and when the fluidized bed boiler is stopped, the water from the makeup water tank is sent to the deaerator. It is equipped with a diesel-powered makeup water pump for this purpose.

According to a fifth aspect of the present invention, instead of the diesel driven makeup water pump of the fourth aspect, a gas turbine driven or emergency power source driven makeup water pump is used.

[0013]

According to the first aspect of the invention, when the fluidized bed boiler is stopped, steam from the fluidized bed boiler is introduced into the feed water pump driving turbine to drive the water feed pump and the water feed booster pump. Further, the steam from the fluidized bed boiler is introduced into the emergency turbine to drive the emergency generator connected to the emergency turbine. Then, the power generated by the emergency generator is supplied to the condensate pump and the condensate booster pump as drive power. Therefore, water supply can be continued even if the fluidized bed boiler stops.

According to the second aspect of the present invention, when the fluidized bed boiler is stopped, the steam from the fluidized bed boiler is introduced into the feed water pump driving turbine to drive the water feed pump and the feed water booster pump. Further, since the emergency generator provided in connection with the feed water pump drive turbine is driven, the power generated by this emergency generator is supplied to the condensate pump and the condensate booster pump as drive power. Therefore, water supply can be continued even if the fluidized bed boiler stops.

According to the third aspect of the present invention, in addition to the effect of the second aspect, the drive power sources for the condensate pump and the condensate booster pump can be adjusted appropriately.

According to the fourth aspect of the present invention, when the fluidized bed boiler is stopped, the diesel driven makeup water pump sends water from the makeup water tank to the deaerator.

In the invention of claim 5, the makeup water pump is driven by a gas turbine drive or an emergency power supply drive.

[0018]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing a first embodiment of the present invention. In the fluidized bed boiler power generation plant of the present invention, during its normal operation, coal fuel is injected into the fluidized bed boiler 1 to raise the temperature of the feed water, and evaporated main steam is passed through the steam valve 24 of the main steam pipe 3. First, the high pressure turbine 2 of the main turbine is sent. The steam that has finished its work in the high-pressure turbine 2 is retransmitted to the fluidized-bed boiler 1 in the low-temperature reheat pipe 12, heated again, and sent to the intermediate-pressure turbine 14 via the steam valve 25 of the high-temperature reheat pipe 13. It Then, the steam that has finished its work in the intermediate-pressure turbine 14 is further sent to the low-pressure turbine 15, and the low-pressure turbine 15 performs its work.

The generator 16 to which the rotational energy is transmitted by these main turbines (high-pressure turbine 2, medium-pressure turbine 14, low-pressure turbine 15) converts the kinetic energy due to its rotation into electric energy, which is necessary in the power plant. Power is transmitted to the power source and the internal and external systems. The steam finally discharged from the low-pressure turbine 15 is condensed in the condenser 17 and returned to water. Cooling water is sent to the condenser 17 by a circulating water pump 18.

Condensate in the condenser 17 is boosted by the electric motor-driven condensate pump 6 and the electric motor-driven condensate booster pump 7 and sent to the deaerator 8. The inside of the deaerator 8 is a facility that can store water for about 3 minutes of the boiler water supply flow rate. The water supply is the water supply booster pump 9 and the water supply pump 1.
The pressure is increased at 0 to supply water to the fluidized bed boiler 1. The water supply booster pump 9 and the water supply pump 10 are driven by a water supply pump drive turbine 11. In addition, the water supply pump drive turbine 1
1 is driven by the extraction air of the intermediate pressure turbine 14 obtained via the steam valve 26. In FIG. 1, two water supply pumps are drawn, but the water supply pump 10 surrounded by a dotted line is the same.

In the fluidized bed power plant of the present invention, the steam from the fluidized bed boiler 1 is also guided as the steam source of the feed water pump 11. That is, the steam pipe 30 that branches from the main steam pipe 3 and guides the steam from the fluidized bed boiler 1 via the steam valve 27 is provided, and the steam due to the residual heat amount of the fluidized bed boiler 1 when the fluidized bed boiler 1 stops Is configured to be guided to the water supply pump drive turbine 11.

Further, an emergency turbine 4 driven by steam from the fluidized bed boiler 1 is provided, and when the fluidized bed boiler 1 is stopped, steam due to the residual heat amount of the fluidized bed boiler 1 is passed through a steam valve 28 to an emergency state. It is configured to lead to the turbine 4 for use. An emergency generator 5 is connected to the emergency turbine 4, and various pumps (condensate pump 6, condensate booster pump) that supply water to the fluidized bed boiler 1 with electric power generated by the emergency generator. 7. It becomes the power source for driving the circulating water pump 18).

Here, when an accident occurs in the external power transmission system of the power generation plant, the power generation plant makes an emergency stop. As a result, the fluidized bed boiler 1, the main turbine and the generator 16 are brought to an emergency stop. Therefore, when the fluidized bed boiler 1 is a boiling fluidized bed boiler in particular, the fluidized bed coal fuel and the bed material in the furnace retain a large amount of heat even after the boiler is stopped. Therefore, it is necessary to send cooling water to the fluidized bed boiler 1 for cooling.

FIG. 2 shows the characteristics of the amount of cooling water supplied. As shown in FIG. 2, as the cooling water, the boiler maximum evaporation flow rate B-MCR is sent for about 5 minutes after the fluidized bed boiler 1 is stopped, and then the cooling water is gradually reduced while finally reducing the feed water flow rate. It will take about 20 minutes for the water supply to stop.

The feed water pump drive turbine 11 is operated by extraction of air from the intermediate pressure turbine 14 during normal operation, but when the intermediate pressure turbine 14 is stopped, the steam valve 24 is closed and the steam valve 27 is opened to drive the steam source. From main steam pipe 3 to steam pipe 3
Switch to 0. As a result, the feedwater pump drive turbine 11 is continuously operated even after the main turbine is stopped. In the deaerator 8, the boiler maximum evaporation flow rate (B-MC
Since the supply water for about 3 minutes (R flow rate) is stored, the water is supplied to the fluidized bed boiler 1 by the water supply pump 10 using the main steam as a power source and the water supply booster pump 9 directly connected to the water supply pump 10.
Will be supplied with water.

The stored water in the deaerator 8 is replenished by the condensate pump 6 and the condensate booster pump 7. The drive power of the condensate pump 6 and the condensate booster pump 7 is obtained from the generator 16 connected to the main turbine during normal operation, but when the main turbine and the generator 16 are stopped or an external power system accident occurs. Since the emergency turbine 4 and the emergency power generator 5 are driven by the main steam generated by the residual heat amount in the fluidized bed boiler 1, the power generated by the emergency power generator 5 is used as a drive power source.

That is, since the electric power generated by the emergency generator 5 is supplied to the condensate pump 6, the condensate booster pump 7 and the circulating water pump 18, a pump for supplying water to the fluidized bed pump 1 is provided. Will be operated continuously without stopping. As a result, the amount of water stored in the deaerator 8 is kept constant. That is, the amount of water stored in the deaerator 8 is kept constant by the condensate pump 6 and the condensate booster pump 7, and is stably supplied.

As described above, the residual heat amount in the fluidized bed boiler 1 is worked by the feed water pump driving turbine 11 and the emergency turbine 4, so that the thermal energy can be effectively utilized. The steam discharged from the feed water pump driving turbine 11 and the emergency turbine 4 is heat-exchanged with the cooling water which is collected in the condenser 17 and sent by the circulating water pump 18. Then, it is condensed and liquefied there, and the inside of the condenser 17 is maintained at a vacuum degree that is stable for operation.

As described above, according to the first embodiment,
Even if an external power system accident occurs and the fluidized bed boiler power plant is shut down in an emergency, the emergency generator connected to the emergency turbine secures the drive power for the various pumps that supply water to the boiler. It does not damage the tube. Further, since the heat source remaining in the fluidized bed boiler is used as the drive steam source for the emergency turbine, the heat energy can be effectively utilized.

Next, FIG. 3 shows a block diagram of a second embodiment of the present invention. The second embodiment is different from the first embodiment in that the emergency turbine 4 is omitted, the emergency generator 5 is connected to the boiler feed water pump driving turbine 11, and the flow rate of the water supply pump 10 is controlled. The control valve 19 is provided. Therefore, when the fluidized bed boiler 1 is stopped, the boiler feedwater drive turbine 11 drives the feedwater pump 10 and the feedwater booster pump 9 and also the emergency generator 5 to drive the condensate pump 6 and the condensate booster pump. The power supply for driving No. 7 will be supplied.

The boiler feed pump driving turbine 1
1 is not necessarily driven so as to control the feed water flow rate as in the first embodiment, and may be driven by giving priority to the driving power source of the condensate pump and the condensate booster pump. A control valve 19 for controlling the flow rate is provided. Since the other structure is the same as that of the first embodiment shown in FIG. 1, the same reference numerals are given to the same elements and the description thereof will be omitted.

Similar to the first embodiment, when the fluidized bed boiler 1 is stopped, the feed water pump driving turbine 11 is operated by the steam due to the residual heat amount in the fluidized bed boiler 1 to cool the cooling water to the fluidized bed boiler 1. And the electric power generated by the emergency generator 5 is secured as a drive power source for the condensate pump 6 and the condensate booster pump 7. Further, since it is desirable that the emergency power generator 5 be operated at a constant rotation speed, the second embodiment also operates at a constant rotation speed. Therefore, the control valve 19 properly controls the supply flow rate and pressure of the water supply pump 10.
As a result, stable cooling water can be sent to the fluidized bed boiler 1.

Next, FIG. 4 shows a third embodiment of the present invention. The third embodiment differs from the second embodiment in that the emergency generator 5 is connected to the water feed pump drive turbine 11 via the fluid coupling 20 and the control valve 19 is omitted. By connecting the emergency power generator 5 to the water feed pump drive turbine 11 via the fluid coupling 20, it becomes possible for the water feed pump 10 and the emergency power generator 5 to rotate at different rotational speeds, and to the fluidized bed boiler 1. Even if the rotation speed of the water supply pump drive turbine 11 is changed according to the water supply flow rate of 1, the rotation speed of the emergency generator 5 can be rotated at a constant speed. Therefore, the control valve 19 for controlling the supply flow rate and pressure of the water supply pump 10 is omitted. Since other configurations are the same as those of the second embodiment shown in FIG. 3, the same components are designated by the same reference numerals and the description thereof will be omitted.

Similar to the second embodiment, when the fluidized bed boiler 1 is stopped, the feed water pump drive turbine 11 is operated by the steam due to the residual heat amount in the fluidized bed boiler 1 to cool the cooling water to the fluidized bed boiler 1. And the electric power generated by the emergency generator 5 is secured as a drive power source for the condensate pump 6 and the condensate booster pump 7. Further, the flow rate and pressure of the cooling water supplied to the fluidized bed boiler 1 are controlled by the rotation speed of the water supply pump driving turbine. On the other hand, since it is desirable that the emergency generator 5 be operated at a constant rotation speed, the emergency generator 5 is also operated at a constant rotation speed in this third embodiment. Therefore, the rotational speed of the emergency generator 5 is adjusted by the fluid coupling 20. This allows
It becomes possible to send stable cooling water to the fluidized bed boiler 1.

That is, in the third embodiment, instead of the regulating valve 19, the feed pump driving turbine 11 and the emergency generator 5 are used.
Are connected via a fluid coupling 20, and the water supply pump 10 and the emergency generator 5 are operated at different rotation speeds. That is,
By always stably supplying the required cooling water amount and pressure to the fluidized bed boiler 1 and the electric power supplied to the necessary auxiliary equipment, it becomes possible to continuously supply stable cooling water to the fluidized boiler 1.

FIG. 5 shows a fourth embodiment of the present invention. The fourth embodiment differs from the first embodiment shown in FIG. 1 in that, instead of the emergency turbine 4 and the emergency generator 5, makeup water for storing makeup water for supplying water to the fluidized bed boiler 1 is stored. Tank 2
1 and make-up water tank 2 when fluidized bed boiler 1 stops
A diesel-driven make-up water pump 22 for sending water from No. 1 to the deaerator 8 and a deaerator water level control valve 23 are provided. As a result, stable water supply to the fluidized bed boiler 1 can be performed even if the fluidized bed boiler power generation plant is urgently stopped due to an accident in the offshore system by the single diesel-powered makeup water pump 22 that does not depend on the outside system. It will be possible. Since the other structure is the same as that of the first embodiment shown in FIG. 1, the same reference numerals are given to the same elements and the description thereof will be omitted.

During normal operation, water is supplied to the deaerator 8 by the condensate pump 6 and the condensate booster pump 7. Further, since water is lost in the turbine cycle of the fluidized bed power plant, the makeup water in the makeup water tank 21 is supplied to the water supply system by the makeup water pump 22 to compensate for the loss. In this case, the makeup water pump 22 is driven by an electric motor.

On the other hand, when the fluidized bed power plant is stopped, this drive source is driven by diesel. Therefore, the operation can be continued even when all the stations are stopped. When the fluidized bed power plant is stopped, the stored water in the makeup water tank 21 bypasses the condensate pump 6 and the condensate booster pump 7 stopped due to the loss of power in the plant by the makeup water pump 22 driven by diesel to adjust the deaerator water level. Water is sent to the deaerator 8 through a pipe connected to the temporary side of the valve 23.

By supplying water to the deaerator 8, the water storage of the deaerator 8 can be utilized. Further, the dewatering device water level control valve 23 keeps a constant water level in the deaerator 8 so that stable water supply to the fluidized bed boiler 1 can be ensured. For storing water in the deaerator 8, the drive steam source is switched to the main steam pipe 3 by stopping the intermediate pressure turbine 14, and the main steam generated by the residual heat in the fluidized bed boiler 1 is used as a power turbine 11 for driving the feed pump. To drive. As a result, the water supply pump 10 and the water supply booster pump 9 directly connected to the water supply pump 10 are driven to supply water to the fluidized bed boiler 1.

Since the residual heat energy in the fluidized bed boiler 1 is worked by the feed water pump driving turbine 11, the heat energy can be effectively utilized. The steam discharged from the feed water pump drive turbine 11 is collected in the condenser 17, and the makeup water supplied from the makeup water pump 22 to the condenser 17 is sprayed in the condenser 17 to form a spray.
Heat exchange, condensation and liquefaction. The condensed water is appropriately discharged from the lower part of the condenser 17 to the outside of the system.

According to the fourth embodiment, even when an accident occurs in the external system of the fluidized bed power plant and the power plant is stopped in an emergency, the diesel-powered makeup water pump 22 is not affected by the local power system. Cooling water can be supplied to the fluidized bed boiler 1. That is, the diesel-powered makeup water pump 22 sends the stored water in the makeup water tank to the deaerator 8. On the other hand, the steam generated by the residual heat of the boiler is used to drive the boiler feed water pump turbine 11, and the feed water pump 10 can always ensure stable water supply to the fluidized bed boiler 1.

Therefore, even in the case of the total stoppage in the plant, it is possible to prevent the cold blow-off in the furnace of the fluidized bed boiler 1 and to safely stop the fluidized bed boiler power plant without stopping the water supply to the fluidized bed boiler 1. To do.

In the above description, the case where the makeup water pump 22 is driven by a diesel engine has been described, but instead of the diesel-powered makeup water pump 22, a gas turbine-driven or emergency power source-driven makeup water pump may be used. . When the emergency power supply is used, the capacity of the makeup water pump 22 is estimated in advance to prepare the emergency power supply. In this case, since it is not necessary to install a diesel facility for driving the makeup water pump 22, the facility can be rationalized.

[0044]

As described above, according to the present invention, stable cooling water is supplied to the furnace of the fluidized bed boiler even during a total power outage in the power plant due to the stop of the external power supply system of the fluidized bed boiler power plant. be able to. Therefore, it is possible to restart the fluidized-bed boiler in the same required time as when the boiler is stopped normally, even if the fluidized-bed boiler is in an emergency stop without requiring cold blow-off.

That is, according to the first aspect of the present invention, even when the fluidized bed boiler power plant is stopped urgently, the emergency generator connected to the emergency turbine drives various pumps for supplying water to the fluidized bed boiler. It secures the power supply so that the boiler tube is not damaged. Further, since the heat source remaining in the fluidized bed boiler is used as the drive steam source for the emergency turbine, the heat energy can be effectively utilized.

According to the second aspect of the invention, since the feed water pump and the emergency generator are connected to the feed water pump driving turbine, the emergency turbine is not required. Moreover, the same effect as that of the invention of claim 1 can be obtained.

According to the invention of claim 3, since the feed water pump driving turbine and the emergency generator are connected through the fluid coupling, in addition to the effect of the invention of claim 2, the fluid coupling can be used for the emergency generator. The effect that the number of rotations can be adjusted is obtained. Therefore, the rotation speed of the emergency generator can be controlled to be constant even if the rotation speed of the feed water pump driving turbine is controlled according to the flow rate of water supplied to the fluidized bed boiler.

According to the fourth aspect of the invention, since the makeup water pump for starting diesel is used, the cooling water can be supplied to the fluidized bed boiler 1 without being influenced by the power supply system in the plant.

According to the fifth aspect of the invention, since the makeup water pump is driven by the emergency power source, it is not necessary to install a diesel facility for driving the makeup water pump, and the facility can be rationalized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a water supply amount characteristic of cooling water supply when a fluidized bed boiler is stopped.

FIG. 3 is a configuration diagram showing a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing a third embodiment of the present invention.

FIG. 5 is a configuration diagram showing a fourth embodiment of the present invention.

[Explanation of symbols]

 1 Fluidized Bed Boiler 2 High Pressure Turbine 3 Main Steam Pipe 4 Emergency Turbine 5 Emergency Generator 5 Condensate Pump 7 Condensate Booster Pump 8 Deaerator 9 Water Supply Booster Pump 10 Water Supply Pump 11 Water Supply Pump Drive Turbine 12 Low Temperature Reheat Steam Pipe 13 High-temperature reheat steam pipe 14 Medium-pressure turbine 15 High-pressure turbine 16 Generator 17 Condenser 18 Circulating water pump 19 Control valve 20 Fluid coupling 21 Make-up water tank 22 Make-up water pump 23 Deaerator water level control valve 24-28 Steam valve

Claims (5)

[Claims] 1. A steam from a fluidized bed boiler having a residual heat quantity is guided to a main turbine, steam that has finished work in this main turbine is condensed in a condenser, and condensed water from this condenser is condensed into a condenser pump. And, in the fluidized bed boiler power plant, which led to the deaerator by the condensate booster pump, and supplied the water of this deaerator to the fluidized bed boiler by the feed water pump and the water booster pump, the fluidized bed boiler stopped. When the steam from the fluidized bed boiler is provided with a steam line for introducing the feed water pump and the feed water pump driving turbine that drives the feed water booster pump, when the fluidized bed boiler is stopped, it is driven by the steam from the fluidized bed boiler. An emergency turbine is provided, and an emergency generator for supplying power for driving the condensate pump and the condensate booster pump is connected to the emergency turbine. A fluidized bed boiler power plant characterized by being provided. 2. A steam from a fluidized bed boiler having a residual heat quantity is guided to a main turbine, steam which has finished work in the main turbine is condensed in a condenser, and condensed water from the condenser is condensed into a condensate pump. And, in the fluidized bed boiler power plant, which led to the deaerator by the condensate booster pump, and supplied the water of this deaerator to the fluidized bed boiler by the feed water pump and the water booster pump, the fluidized bed boiler stopped. At this time, a steam line for introducing steam from the fluidized bed boiler to a feed water pump drive turbine for driving the feed water pump and the feed water booster pump is provided to supply power for driving the condensate pump and the condensate booster pump. A fluidized-bed boiler power plant, wherein the emergency generator is connected to the feed water pump driving turbine. 3. The fluidized bed boiler power plant according to claim 2, wherein the emergency generator is connected to the feed water pump driving turbine through a fluid coupling. 4. The steam from the fluidized bed boiler having a residual heat quantity is guided to a main turbine, the steam that has finished its work in the main turbine is condensed in a condenser, and the condensed water from the condenser is condensed into a condensate pump. And the condensate booster pump leads to the deaerator, and the water of the deaerator is supplied to the fluidized bed boiler in a fluidized bed boiler power plant configured to supply the fluidized bed boiler with the water supply pump and the water supply booster pump. A makeup water tank for storing makeup water for storing, and a diesel-driven makeup water pump for sending water from the makeup water tank to the deaerator when the fluidized bed boiler stops. Fluidized bed boiler power plant. 5. The fluidized bed boiler power plant according to claim 4, wherein the diesel driven makeup water pump is replaced by a gas turbine driven or emergency power source driven makeup water pump.