JPH09112801A - Pressurized fluidized bed boiler power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To store hot water without needing to normally heat water stored in a hot water tank by a method wherein hot water generated by a steam separator is fed to a hot water tank. SOLUTION: During a rated output at a normal running period, feed water is boosted to a rated pressure by a condensate pump 19 and a boiler feed water pump 21 and flows in a water-cooled wall 3, being a first boiler heat transfer pipe, through a feed water flow rate regulation valve 36. Further, feed water flows through a vaporizer 4 to produce steam, which flows to a steam separator 5. Hot water generated by a steam separator 5 is guided to a hot water tank 27 through a piping and a piping flow rate is controlled by a flow rate regulation valve 29. Steam producing superheated steam passing through a superheater 10 flows in a high pressure turbine on the high pressure side of a steam turbine 14. Steam passing through the high pressure turbine is guided to a boiler again and superheated by a reheater 11 and flows to the middle pressure side of the steam turbine 14. As noted above, a boiler circulation line is formed into a signal line and by feeding high temperature drain to the hot water tank 27, storage water is kept at temperature approximately equal to a saturated temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressurized fluidized bed boiler power generation system, and more particularly, to a structure of pump piping equipment to reduce the output of the pressurized fluidized bed boiler or to an in-bed heat transfer tube when an emergency stop occurs. The present invention relates to a pressurized fluidized bed boiler power generation system suitable for ensuring water injection.

[0002]

2. Description of the Related Art As an example of a system configuration for cooling an in-bed heat transfer tube at the time of an emergency stop of a pressurized fluidized bed boiler, one disclosed in U.S. Pat. No. 4,911,107 is known. There is. In this conventional technique, an emergency hot water tank pressurized with gas, which is provided to inject hot water instead of supplying water when the plant is shut down, a superheater (hereinafter abbreviated as SH), and a reheater (hereinafter , RH) for the purpose of ensuring a flow rate of cooling steam. Further, Japanese Patent Laid-Open No. 6-281103 discloses a configuration example in which a hot water tank for heating stored water is installed and hot water in the hot water tank is supplied to the heat transfer tube section by gravity difference in an emergency.

The pressurized fluidized bed boiler power generation system described in JP-A-6-281103 is as shown in FIG. According to this configuration example in which the emergency hot water tank is installed at a high place and has a gravity head, the emergency hot water tank 1 to the water cooling wall 3 and the evaporator 4 are replaced in place of the water supply pump at the initial stage of the emergency stop.
Water is injected into the heat transfer tube of No. 2 and at the same time, the atmosphere release valves 12A and 12B at the SH / RH outlet are opened to cool the in-layer heat transfer tube. When the amount of water stored in the emergency hot water tank 1 is exhausted by pouring water, the emergency water supply pump 20 is switched to water supply. When the temperature of the furnace layer decreases with the lapse of time after the furnace is stopped and the amount of heat absorbed by the in-layer heat transfer tubes decreases, a two-phase flow occurs at the evaporator outlet, so hot water accumulates in the steam separator 5. In this case, the hot water is circulated by activating the boiler circulation pump 8 installed in the circulation line on the outlet side of the brackish water separator 5 or opening the bypass valve 6. It should be noted that the boiler circulation pump 8 is operated to circulate the hot water because a two-phase flow is generated at the evaporator outlet even at the time of low output in the normal operation. In addition, JP-A-6-14740
In JP No. 5 publication, a head tank is provided, a part of the discharge water of the water supply pump is heated by a heat exchanger and guided to the head tank, and this discharge water is guided to a brackish water separator to be supplied in an emergency. Is listed.

[0004]

In the above-mentioned conventional pressurized fluidized bed boiler power generation system, the heater 22 installed inside the emergency hot water tank 1 is used to electrically heat the tank water so that the tank water is always close to the saturation temperature. Need to keep. Alternatively, it is necessary to raise the temperature through heat exchange. On the other hand, during normal operation, it is not necessary to inject water using the emergency hot water tank during output increase from the boiler start during rated operation and during stop operation.
The facility operation efficiency of the emergency hot water tank is quite low. In addition, at the time of emergency stop of the boiler, it is necessary to switch from the operation mode in which the outlet valve of the emergency hot water tank is opened for water injection to the operation mode in which the bypass valve of the boiler circulation pump is opened and the boiler circulation line is used. It was a little complicated.

A first object of the present invention is to provide a pressurized fluidized bed boiler power generation system for storing hot water without requiring constant heating of the emergency hot water tank storage by a heater which increases operating costs. is there.

A second object of the present invention is to utilize the emergency hot water tank facility even during starting and stopping of normal operation, and to eliminate the need for the operation of pouring water from the hot water tank and switching to the boiler circulation line. It is to provide a boiler power generation system.

[0007]

In order to achieve the first object, the pressurized fluidized bed boiler power generation system of the present invention comprises:
A pressurized fluidized bed boiler, a water cooling wall that exchanges heat with a layer in the fluidized bed of the pressurized fluidized bed boiler, an evaporator installed on the downstream side of the water cooling wall, and an outlet side of the evaporator. And a steam turbine for separating steam and water, a superheater and a reheater installed on the outlet side of the steam water separator, a steam turbine driven by steam from the superheater and the reheater, and Pressurized fluidized bed boiler power generation including a generator driven by a steam turbine, a water supply system for supplying water to the water cooling wall, the evaporator, the superheater and the reheater, and a hot water tank for injecting hot water into the in-bed heat transfer tubes. The system is characterized in that hot water generated from the brackish water separator is supplied to the hot water tank.

In order to achieve the above-mentioned second object, the pressurized fluidized bed boiler power generation system of the present invention comprises a hot water tank with a brackish water separating function, which is integrally formed by joining the brackish water separator to the upper part of the hot water tank. It is composed. A pump and a hot water tank outlet valve are provided between the brackish water separator and the hot water tank, and hot water generated from the brackish water separator is adjusted by adjusting the opening degree of the hot water tank outlet valve. It controls the flow rate by pouring water into the tank. A pump is provided in the water injection line of the hot water tank.

With the above-mentioned structure, as a means for keeping the stored water in the hot water tank near the saturation temperature, a small amount of saturated water is supplied and exchanged with the stored water, whereby the amount of heat loss dissipated from the tank surface. To make up for. During the rated operation of the boiler, there is a single-phase flow of steam at the evaporator outlet, but even in this case, a small amount of high-temperature drain water is constantly generated in the brackish water separator. Based on such knowledge, the present invention can always keep the stored water in the hot water tank at a value close to the saturation temperature without using heater equipment by continuously taking in the drain water of the brackish water separator in the hot water tank.

On the other hand, when the output is increasing after the start of the normal operation, or when the output is decreasing until it stops, a two-phase flow is generated at the evaporator outlet, so that a large amount of hot water is generated in the brackish water separator. For this reason, in the conventional technique, a circulation line is provided to circulate the drain water of the brackish water separator to the heat transfer tube, and the boiler circulation pump and the bypass valve are provided in the middle of the circulation line. On the other hand, in the present invention, focusing on the fact that the boiler circulation line of the prior art can be substituted by the water injection line of the hot water tank, the drain water generated in the brackish water separator is warmed even during low output during normal operation. It was taken in by the tank, and the tank outlet valve was opened to inject the stored water into the heat transfer tube. This eliminates the need to switch from the hot water tank water injection line to the boiler circulation line when an emergency boiler is stopped, and the conventional boiler circulation line piping and pump equipment are not required, so the system configuration can be rationalized. .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIGS.
This will be described below. FIG. 1 is a configuration diagram of a pressurized fluidized bed boiler power generation system of this embodiment, and FIG. 2 is a diagram showing a simulation result of a boiler emergency stop of the pressurized fluidized bed boiler power generation system of this embodiment.

As shown in FIG. 1, the pressurized fluidized bed boiler power generation system of the present embodiment mainly comprises a gas turbine 13, a pressurized fluidized bed boiler (not shown), a steam turbine 14, a generator 17, and a low pressure side of the steam turbine. It is composed of a condenser 18 provided on the downstream side, a water / steam system, and the like. The discharge air from the compressor of the gas turbine 13 is supplied to a pressurized fluidized bed boiler and used for combustion of coal in the pressurized fluidized bed boiler. The combustion gas is introduced into the turbine of the gas turbine 13 and then exhaust heat is removed. Superheater 10 and reheater 11 in the recovery boiler
The exhaust heat is recovered by the above and drives the steam turbine 14.

The water / steam system is constructed as follows. On the downstream side of the condenser 18, there are provided a condensate pump 19, a boiler feed pump 21, and an emergency feed pump 20 in parallel with the boiler feed pump 21, which is branched on the downstream side and one of which is a spray valve. 26, the other is connected to the water cooling wall 3, the evaporator 4, and the brackish water separator 5 sequentially through the feed water flow rate control valve 36. The lower side of the brackish water separator 5 is connected to the hot water tank 27 via the flow rate control valve 29, the upper side of the brackish water separator 5 is connected to the superheater 10, and the reheater 11 via the valve 9. It is branched between the brackish water separator 5 and the superheater 10, and is connected to the hot water tank 27 via the valve 7. The lower side of the hot water tank 27 is connected to the pipe between the water supply flow rate control valve 36 and the water cooling wall 3 via the tank outlet valve 2. The water level of the hot water tank 27 and the water level of the brackish water separator are indicated by the signal lines 34 and 35, respectively.
It is connected to the water level controller 27 and controls the drain valve 28, the tank outlet valve 2, and the feed water flow rate control valve 36 provided between the hot water tank 27 and the tank outlet valve 2. Here, the warm water tank 27 is installed at a high place so that a sufficient amount of water to be injected can be secured by the gravity head without using power such as a pump at the time of emergency stop.

The superheater 10 has an air release valve 12A,
The steam turbine 13 is connected to the inlet side of the high pressure turbine via a pipe provided with the high pressure turbine control valve 15, and the outlet side of the high pressure turbine is connected to the reheater 11. The downstream side of the reheater 11 is connected to the intermediate pressure turbine of the steam turbine 13 via the atmosphere release valve 128 and the medium / low pressure turbine control valve 16, while being connected to the condenser 18 via the bypass valve 24. . Further, the condenser 18 is connected to the downstream side of the drain valve 28 described above. The outlet side of the medium pressure turbine is connected to the low pressure turbine. The intermediate portion between the superheater 10 and the high pressure turbine and the intermediate portion between the high pressure turbine and the reheater 11 are connected via a bypass valve 23 and a spray 25, and the spray valve 26 is connected to the spray valve 26 described above. There is.

Next, the operation of the pressurized fluidized bed boiler power generation system configured as described above will be described.

At the rated output during normal operation, the feed water is boosted to the rated pressure by the condensate pump 19 and the boiler feed water pump 21, and passes through the feed water flow control valve 36 to enter the water cooling wall 3 which is the first boiler heat transfer pipe. The supplied water becomes vapor through the evaporator 4, enters the brackish water separator 5, guides the hot water generated in the brackish water separator 5 to the hot water tank 27 by a pipe, and controls the flow rate of the pipe by the flow rate control valve 29. The steam that has become superheated steam through the superheater 10 enters the high pressure turbine on the high pressure side of the steam turbine 14, and the steam that has passed through the high pressure turbine is
It is again guided to the boiler, overheated by the reheater 11, and enters the medium and low pressure side of the steam turbine 14.

When an emergency event such as a total stop of the plant or a trip of the water supply system occurs at this plant, the fuel system first trips to stop combustion of the fluidized bed of the furnace.
The tank outlet valve 2 of the hot water tank 27 is opened, the steam atmosphere release valves 12A and 12B are opened, and the RH cooling valve 9 is opened. The purpose of operating the heat transfer tube protection system is to secure the feed water flow rate to the water cooling wall 3 and the evaporator 4, and to secure the cooling steam flow rate of the superheater 10 and the reheater 11. First, securing the flow rate of water supply to the water cooling wall 3 and the evaporator 4 is performed by injecting warm water close to saturated water from the warm water tank 27 at the initial stage of the emergency stop (about 10 minutes), and then the emergency water supply. The pump 21 is started and water supply is added. By injecting warm water from the warm water tank 27 instead of the emergency water supply pump 21 at the initial stage, the amount of steam generated from the evaporator is increased, and the cooling steam flow rate of the superheater 10 and the reheater 11 is increased. Superheater 10 and reheater 1
Securing the cooling steam flow rate of 1 means that the high-pressure turbine control valve 15 and the medium- and low-pressure turbine control valve 16 of the steam turbine 14 are suddenly closed to block the flow of steam at the time of an emergency stop. This is performed by opening the discharge valve 12B.

As shown by the thick line from the water supply to the boiler in FIG. 1 through the brackish water separator 5 to the SH / RH (superheater / reheater), the brackish water separator 5 and the hot water tank 27 are combined to form hot water. The boiler circulation line using the tank water injection line has been integrated. Therefore, by supplying the high temperature drain water generated in the brackish water separator 5 to the hot water tank 27, the stored water can be maintained near the saturation temperature. When the water level of the hot water tank reaches the highest level and the remaining water is stored, open the drain valve 28 and
Return to 8. At the time of low output power increase after start-up or during output drop to stop, the hot water tank outlet valve 2 is opened to inject the stored water into the heat transfer pipe, and the hot water taken in from the steam separator 5 is naturally circulated.

In order to secure the flow of drain water,
In the present embodiment, the case where the installation position height of the brackish water separator 5 is set higher than that of the hot water tank 27 has been described, but this is not the case when the pumping pump is used as described in other embodiments of the present invention.

When the water level of the hot water tank 27 is lowered to the minimum water level by the water injection, the tank outlet valve 2 is closed to stop the water injection. Furthermore, when the time after the boiler trip elapses, the drain water level of the brackish water separator 5 begins to rise because a two-phase flow is formed at the outlet of the evaporator 4 as the furnace layer temperature decreases. At this point, the flow control valve 29 in the drain pipe of the brackish water separator 5 is opened to open the hot water tank 2 in the same manner as in the low output during normal operation.
7. Hot water is sent to 7, and when the tank water level rises, the hot water tank outlet valve 2 is opened to inject the stored water into the heat transfer pipe and circulate it naturally.

The tank flow rate / water level controller 30 is provided to constitute a control system considered necessary when automatically controlling the valve operation of the water / steam system as described above. The tank flow rate / water level controller 30 takes in the steam flow rate 33 at the outlet of the brackish water separator and the signal line (warm water tank water level) 34 so that the absolute value of the difference between the signal line (hot water tank water level) 34 and the target value decreases. And the signal line (hot water tank water level) 34 matches the target value, the opening of the drain valve is adjusted so that the absolute value of the difference between the steam flow rate 33 at the outlet of the brackish water separator and the feed water flow rate decreases. The demand, the opening demand of the tank outlet valve, and the demand demand of the feed water flow control valve are determined, and the signal lines 31, 32, and
35. Note that the control system configuration of the present embodiment shows an example of a configuration in which control is automatically performed, but a manual operation may be performed by an operator.

Using the dynamic characteristics simulator of the pressurized fluidized bed boiler plant, the simulation of the pressurized fluidized bed boiler power generation system of this embodiment and the conventional pressurized fluidized bed boiler power generation system at the time of emergency stop of the boiler were compared. The results are shown in Figure 2. As shown in FIG. 2, in both the present embodiment and the conventional technology, at the initial stage after the boiler trip, the hot water tank outlet valve is opened to pour water from the hot water tank into the heat transfer tube, but when the time is about 580 seconds, the tank water storage reaches the minimum. Since the water level has been reached, close the tank outlet valve and start the emergency water supply pump. In this case, the flow rate of water injection is not controlled, so the opening of the outlet valve is fully opened, the outlet flow rate of the hot water tank is small at the beginning, and the fluid density of the water cooling wall and the evaporator decreases, and the gravity head It is increasing as the difference rises. Since a two-phase flow occurs at the evaporator outlet after about 1000 seconds has elapsed and drain water is generated in the brackish water separator, the conventional technology does not use a hot water tank.
Although the water level of the brackish water separator starts to rise, in this embodiment, the drain water is sent to the hot water tank, so the hot water tank water level is rising. Here, the hot water tank is a horizontal tank, and the cross-sectional area of the hot water tank is about 50 times that of the brackish water separator.
Since it is double, the change in water level is small. In the conventional technique, when the time has passed about 2400 seconds, the brackish water separator water level reaches the maximum water level, the emergency water supply pump is stopped, the bypass valve of the boiler circulation pump is opened, and the natural circulation mode is set.

In the initial stage of the natural circulation mode, the water level in the brackish water separator is high, so the circulation flow rate is large, but the flow rate decreases as the water level decreases due to evaporation. On the other hand, in the present embodiment, the water level of the hot water tank reaches the maximum water level at the time when about 2800 seconds have elapsed, the emergency water supply pump is stopped, the hot water tank outlet valve is opened, and water injection is started to allow natural circulation. Enter the mode.

Since the steam flow rate of the superheater (SH) and the steam flow rate of the outlet of the reheater (RH) become a critical flow at the atmosphere release valve at the SH / RH outlet, they decrease almost in proportion to the system pressure. There is. Here, changes in the steam temperature at the SH outlet where the temperature rises severely and in the furnace fixed bed temperature in contact with the SH heat transfer tube are shown. However, the rise in the steam temperature at the SH outlet is small, and the limit value (650 ° C here) is exceeded. You can see that there is enough room.

A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing a system configuration of the pressurized fluidized bed boiler power generation system of the present embodiment.

The difference between this embodiment and the first embodiment is that, as means for sending the drain water of the brackish water separator to the hot water tank, a brackish water separator is integrated by joining a brackish water separator above the hot water tank 27. This is because the hot water tank 40 with a separating function is used, and this brackish water separator has a bypass valve 41 and a boiler circulation pump 42 provided in parallel at the lower portion of the hot water tank 40.

The advantage of this embodiment is that the drain pipe and the flow control valve 24 are not required, and the hot water tank and the brackish water separator are integrated into a compact shape as a whole, which reduces the construction and manufacturing costs. It is possible.
Here, the function of the system of the present embodiment is the same as that of the first embodiment and is essentially the same, and the contents of the driving operation at the time of normal operation and at the time of emergency stop are also the same, but in the present embodiment, As shown in FIG. 3, since the boiler circulation pump 42 and its bypass valve 41 are installed in the water injection line of the hot water tank 40 with a brackish water separation function, the two-phase flow at the evaporator outlet at the time of low output in normal operation. However, in an operating condition in which hot water is circulated using the water injection line, the boiler circulation pump 42 is used to ensure a stable and sufficient circulation flow rate. Here, the brackish water separation function hot water tank 40 is installed at a high place in order to secure a sufficient water injection flow rate even in an emergency when the electric pump cannot be used. Therefore, the natural circulation operation without using the boiler circulation pump 42 is performed. Even in the mode, a larger flow rate can be obtained than in the conventional boiler circulation line.

A third embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a diagram showing a system configuration of the pressurized fluidized bed boiler power generation system of the present embodiment, and FIG. 5 is a diagram showing simulation results at the time of an emergency stop of the boiler of the pressurized fluidized bed boiler power generation system.

The difference between the present embodiment and the first embodiment is that the brackish water separator 5 is installed at a lower position than the hot water tank 27, and the drain water is installed in the hot water tank 27. That is, the pumping pump 43 is used as a means for sending to. Therefore, there is an advantage that there is less restriction on the plant construction for the set position of the brackish water separator 5, but there are also disadvantages that the installation of the pumping pump 43 increases the cost and the operation method of the system becomes complicated.

The operation method of the system of this embodiment will be described below. The difference from the first embodiment is the method of operating the pump pump 43 and the water level control method of the brackish water separator 5 associated therewith. At the rated output in normal operation, the amount of hot drain water generated in the brackish water separator 5 is small,
When the water level of the brackish water separator 5 rises to the target point, the flow rate control valve (pump inlet valve) 44 is opened, the pump 43 is intermittently operated, and hot water is supplied to the hot water tank 27 to store water. Keep near the saturation temperature. The excess water stored when the water level of the hot water tank reaches the highest level opens the drain valve 46 and returns it to the condenser 18. Similarly, at the time of low output power rising or power output falling to stop, the pump pump 43 is also intermittently operated to open the tank outlet valve 2 of the hot water taken in from the brackish water separator 5 to open the heat transfer tube. Pour water into the water and let warm water circulate.

At the time of an emergency stop of the boiler, the tank outlet valve 2 is opened at the initial stage to inject hot water from the hot water tank 27, and when the water level of the hot water tank 27 is lowered by the water injection to reach the minimum water level, the tank outlet valve 2 is closed. And stop water injection.
Furthermore, when a two-phase flow occurs at the outlet of the evaporator 4 after a lapse of time after the boiler trip, the drain water level of the brackish water separator 5 begins to rise, so that the pumping pump is intermittently pumped as in the low output of normal operation. 43 is operated, and when the tank water level rises, the hot water tank outlet valve 2 is opened to inject the stored water into the heat transfer tube and circulate it naturally.

The tank flow rate / water level controller 50 is for automatically controlling the valve operation of the water / steam system,
The tank flow rate / water level controller 50 takes in the water level of the hot water tank 27 and the water level of the brackish water separator via the signal lines 51 and 52, respectively, so that the absolute value of the difference between the target value of the water level of the hot water tank 27 decreases. The flow control valve (pump inlet valve) 44 so that the water level of the brackish water separator 5 is within the target range.
Opening degree request, pumping pump operation request, drain valve 45,
The opening request of 46 and the opening request of the tank outlet valve 2 are determined,
It outputs to the signal lines 53, 55, 54, 56 and 57, respectively. In addition, the control system configuration of the present embodiment is an example of the configuration, even by a manual operation by some operators,
It goes without saying that the valve operation described above is possible.

FIG. 5 shows a simulation result of the pressurized fluidized bed boiler power generation system of the present embodiment when the boiler is stopped in an emergency.
As can be seen from the figure, after the boiler trip, the hot water tank outlet valve is opened and water is poured from the hot water tank to the heat transfer pipe, the tank water reaches the minimum water level, the tank outlet valve is closed, and the emergency water supply pump is started. Was performed under the same conditions as the simulation at the time of the emergency stop of the boiler of the first embodiment, and it was found that similar results were obtained. Here, in the hot water tank water injection at the initial stage, the tank outlet valve is fully opened, and the water injection flow rate control is not performed. Drain water is generated in the brackish water separator after about 111 seconds, and the water level in the brackish water separator begins to rise. At about 1500 seconds, the pumping pump is activated and drain water is transferred to the hot water tank. As it is sent, the water level of the brackish water separator has dropped and the water level of the hot water tank has risen. After that, the pumping pump is intermittently activated due to the change in the water level of the brackish water separator, so the water level of the brackish water separator changes like a saw blade. The hot water tank outlet valve opens at the time when about 2400 seconds have elapsed, and the hot water tank outlet flow rate is controlled to be substantially equal to the target value by the water injection flow rate control.

FIG. 5 shows only the simulation result at the time of the emergency stop of the boiler, but at the time of the low output of the normal operation, when the time elapses after the stop of the furnace at the emergency stop of the boiler, the temperature of the furnace layer decreases. Is almost equal to the condition. As shown in the simulation results, in the pressurized fluidized bed boiler power generation system of the present embodiment, the emergency natural water injection to the heat transfer tubes and the stable natural circulation mode of the boiler feed water are achieved during the emergency stop of the boiler or the low output of the normal operation. It will be possible.

A fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a diagram showing a system configuration of the pressurized fluidized bed boiler power generation system of the present embodiment.

This embodiment differs from the third embodiment described above in that a gas tank 59 is connected to the hot water tank via a pressurization adjusting valve 58, and the hot water tank is of a gas pressurizing type. In this case, the hot water tank does not have to be installed at a high height, which has the advantage of reducing restrictions on plant construction, but requires new gas pressurization equipment such as a gas tank and pressurization control valve. However, there is also a drawback that the cost is increased and the operation method of the system is complicated.
On the other hand, the drain water of the brackish water separator 5 is supplied to the gas pressurized hot water tank 6
As in the third embodiment, it is necessary to use the pumping pump 43 as a means for sending to 0. Since the operation method of the water / steam system is the same as that of the third embodiment described above,
Description is omitted.

[0037]

As described above, according to the present invention,
By continuously taking in the drain water of the brackish water separator in the hot water tank, it is possible to maintain the stored water in the hot water tank at a value close to the saturation temperature without a heater facility. In addition, the drain water generated in the brackish water separator is taken into the hot water tank even during low power output during normal operation, and the tank outlet valve is opened to inject the stored water into the heat transfer tube. Can be possible. This allows
It is not necessary to switch the hot water tank water injection line to the boiler circulation line at the time of emergency stop of the boiler, and the piping and pump equipment of the conventional boiler circulation line are also unnecessary, so that the system configuration can be rationalized.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a pressurized fluidized bed boiler power generation system that is a first embodiment of the present invention.

FIG. 2 is a diagram showing a simulation result of a boiler emergency stop of the pressurized fluidized bed boiler power generation system of the present embodiment.

FIG. 3 is a system configuration diagram of a water / steam system using a hot water tank with a brackish water separating function according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a third embodiment of the present invention in which a drainage water of a brackish water separator is used to send a drain water to a hot water tank;
It is a system configuration diagram of a steam system.

FIG. 5 is a diagram showing a simulation result of a boiler emergency stop of the pressurized fluidized bed boiler power generation system of the present embodiment.

FIG. 6 is a system configuration diagram of a water / steam system when a gas pressurized hot water tank according to a fourth embodiment of the present invention is used.

FIG. 7 is a configuration diagram of a conventional pressurized fluidized bed boiler power generation system.

[Explanation of symbols]

8 ... Boiler circulation pump, 15 ... High pressure turbine regulator valve, 1
6 ... Low-pressure turbine control valve, 29, 44 ... Flow control valve, 3
1, 32, 34, 35, 51, 52, 53, 54, 5
5, 56, 57 ... Signal line, 33 ... Steam flow rate at brackish water separator outlet, 45, 46 ... Drain valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Nakatani 6-9 Takaracho, Kure City, Hiroshima Prefecture Babcock Hitachi Ltd. Kure Factory

Claims (4)

[Claims] 1. A pressurized fluidized bed boiler, a water cooling wall for exchanging heat with a bed in the fluidized bed of the pressurized fluidized bed boiler, an evaporator installed on the downstream side of the water cooling wall, and the evaporator. Driven by steam from the brackish water separator installed at the outlet side of the steam generator, the superheater and reheater installed at the outlet side of the brackish water separator, and the steam from the superheater and reheater A steam turbine, a generator driven by the steam turbine, the water cooling wall,
A pressurized fluidized bed boiler power generation system comprising a water supply system for supplying water to an evaporator, a superheater and a reheater, and a hot water tank for injecting hot water to an in-layer heat transfer pipe, wherein hot water generated from the brackish water separator is A pressurized fluidized bed boiler power generation system, characterized in that the hot water tank is supplied with water. 2. The pressurized fluidized bed boiler power generation system according to claim 1, wherein a hot water tank with a brackish water separating function is configured by joining and integrating the brackish water separator on an upper portion of the hot water tank. 3. A pump and a hot water tank outlet valve are provided between the brackish water separator and the hot water tank, wherein hot water generated from the brackish water separator is adjusted by adjusting the opening degree of the hot water tank outlet valve. The pressurized fluidized bed boiler power generation system according to claim 1, wherein the flow rate of water injection into the hot water tank is controlled. 4. The pressurized fluidized bed boiler power generation system according to claim 1, wherein a pump is provided in a water injection line of the hot water tank.