JPH04194504A - steam power plant - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a steam motor plant, and particularly to a condensate water supply system suitable for supplying stable water supply to a steam generator and a drain-up method thereof.

[Conventional technology]

There is a conventional condensate water supply system, particularly one related to a drain pump system (described in Japanese Patent Application Laid-Open No. 63-223403). A drain pump system similar to this conventional example will be explained using FIG. 6.

The steam generated in the steam generator 1 is passed through the steam generator outlet valve 2.
The exhaust electricity from the high pressure turbine 3 is supplied to the low pressure turbine 5 via the intermediate steam stop valve 4 to rotate the turbine and drive the generator 6. The steam exhausted from the low pressure turbine 5 is transferred to the condenser 7
It is condensed and becomes condensate. This condensate is transferred to the condensate pump 8.
Low pressure feed water heater 10. Water pump 11. It passes through the high pressure feedwater heater 12 and returns to the steam generator 1 . On the other hand, the steam extracted from the middle of the high pressure turbine 3 is transferred to the high pressure feed water heater 1.
At step 2, the condensed water exchanges heat with the supplied water to become drain (condensed water), and is collected in the high-pressure drain tank 14. The drain stored in this tank 14 is passed through the high pressure drain pump inlet valve 16.
The pressure is increased by the high pressure drain pump 17, passes through the high pressure drain pump outlet valve 18, and then passes through the high pressure drain tank water level control valve 19.
The water is collected directly to the inlet of the water supply pump 11 via the water supply pump 11. Also,
Condensate (cold water) from the outlet of the low-pressure feed water heater 10 is directly injected into the high-pressure drain tank I4 via the condensate supply valve 28. Furthermore, a gate valve 29 for closing is provided in a pressure equalizing pipe that balances the internal pressures of the high-pressure feed water heater 12 and the high-pressure drain tank 14. Here, the gate valve 29 and the condensate make-up water valve 28 are configured to be switched via a switching means 27 as necessary, and are switched based on a detection signal from the electrical output detector 26 during a transient change in the plant. The means 27 compares the detected value with the set value and switches the valves 28, 29 to control the pressure in the drain tank 14.

[Problem to be solved by the invention]

In the drain tank pressure control system of the prior art described above, when the plant output suddenly changes due to load interruption of the turbine generator 6, etc., the internal pressure of the drain tank 14 as shown in FIG. 6 temporarily drops significantly. do. At this time, the pressure control of the drain tank cannot follow the drain in the drain pump inlet piping, so a flash phenomenon occurs. When this flash phenomenon occurs, the drain pump 17 trips to protect the pump. Furthermore, in a condensate water supply system in which the drain pump 17 is installed, the water supply processing capacity of the condensate pump 8 is generally only about 60% of the total amount of water supply. For this reason, if the drain pump 17 trips, the water supply from the drain pump 17 disappears, and as a result, the condensate pump 8 runs out, and the inlet pressure of the water pump 11 decreases. The water supply pump 11 stops (trips).

Therefore, there is a risk that the water supply capacity will be lost and the steam generator 1 will scram (automatically stop).

The object of the present invention is to provide a condensate water supply system and a drain up method thereof that can prevent the drain pump from tripping and provide stable water supply to the steam generator even when the plant output changes widely such as during load shedding. Our goal is to provide the following.

[Means to solve the problem]

The above purpose is to reduce the inlet pressure required for the drain pump when a turbine generator load cutoff occurs and the amount of steam flowing into the turbine from the steam generator decreases, resulting in a significant drop in the internal pressure of the drain tank. This is achieved by controlling the amount of cold water injected into the drain pump to ensure this.

In addition, the valve that injects cold water into the drain pump is controlled depending on the operating status of the drain pump or the condensate flow rate, and even when the drain pump trips, the inlet pressure of the standby drain pump is maintained to ensure that the standby drain pump is activated. This is achieved by activating it.

[Function] When the plant output suddenly decreases, or when the amount of steam flowing into the turbine from the steam generator decreases due to load shedding, etc., the internal pressure of the drain tank decreases significantly, but the inlet pressure of the drain pump decreases. Since the pump is operated within its water supply capacity, a stable suction flow rate can be ensured for the water supply pump.

Further, when the drain pump trips, the necessary inlet pressure can be ensured for the drain pump of the standby machine, and stable continuous water supply to the steam generator can be ensured.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a block diagram of a steam motor plant according to an embodiment of the present invention. Steam generated in the steam generator 1 enters the high-pressure turbine 3 via the steam generator outlet valve 2 and performs work, and the exhaust steam from the high-pressure turbine 3 is supplied to the low-pressure turbine 5 via the intermediate steam stop valve 4, and the turbine 5 to drive the generator 6. Steam exhausted from the turbine 5 is condensed in a condenser 7 and becomes condensed water. The condensate is supplied by a condensate pump 8, a condensate flow rate detector [9, a low pressure feed water heater 10. Water pump 11. It passes through the high pressure feedwater heater 12 and returns to the steam generator 1 .

On the other hand, high-temperature steam extracted from the middle of the high-pressure turbine 3 exchanges heat with the feed water in the high-pressure feed water heater 12 and becomes tran (condensed water). The high pressure drain is high pressure drain tank 1
In this embodiment, three high-pressure drain pump inlet valves 16 are provided in parallel, and the pressure is increased by high-pressure drain pumps 17, respectively.

It passes through the high pressure drain pump outlet valve 18 and is directly collected into the water supply pump 11 inlet via the high pressure drain tank water level control valve 19. Further, a portion of the condensate from the outlet of the low-pressure feed water heater 10 is directly injected into the inlet piping of each high-pressure drain pump 17 via three high-pressure drain pump cold water injection valves 21 provided in parallel.

Here, the amount of cold water injected into the inlet piping of each high-pressure drain pump 17 is determined so that the inlet pressure of the pump 17 can be maintained even when a flash phenomenon occurs in the drain tank 14 or in the piping connected to it. It is controlled by a pump operation number determination device 24 and a high pressure drain pump cold water injection control device 23. As a method of changing the cold water injection amount itself, the high pressure drain pump 17 is started or stopped, or
The standby state is determined by the high-pressure drain pump operating number determining device 24, and controlled by a request signal from the high-pressure drain pump cold water conditioning control device 23.

Assume that in the above condensate water supply system, the load on the turbine generator 6 is cut off, and the steam generated by the steam generator 1 suddenly decreases. In the case of answer, since the internal pressure of the high-pressure drain tank 14 drops significantly transiently, a drain flash phenomenon occurs in the inlet piping of the high-pressure drain tank 14 and the high-pressure drain pump 17.

For this reason, it becomes impossible to ensure the required inlet pressure of the high-pressure drain pump 17. Therefore, in the drain pump cold water injection system, the high pressure drain pump operating number disconnect device 2
4, and the high pressure drain pump cold water injection amount itself! 23 is installed and the high pressure drain pump 17 is in operation, the inlet pipe cold water injection valve 21 of the high pressure drain pump 17 that is in operation
At the same time, the high-pressure drain pump inlet pipe cold water injection valve 21 of the standby high-pressure drain pump 17 is also fully opened to ensure the inlet pressure of the high-pressure drain pump 17.

Thereby, it is possible to prevent an abnormality or a pump trip of the high-pressure drain pump 17, and it is also possible to ensure the flow rate of water supply to the water supply pump 11. Note that it is also effective to inject cold water only through the high-pressure drain pump 17 during operation.

FIG. 2 is a configuration diagram of a power generation plant according to a second embodiment of the present invention. The concept of high-pressure drain pump cold water injection is as follows:
This is the same as the first embodiment shown in the figure, but in addition to the configuration of the first embodiment, a cold water injection valve 20 is installed to the high pressure drain pump inlet main pipe 30 in order to make cold water injection more effective. There is. Then, in the same manner as in the first embodiment, the injection valve 20.
21, the amount of cold water injected is equal to the number of operating machines, or the number of operating machines plus the number of waiting machines.

FIG. 3 is a configuration diagram of a power generation plant according to a third embodiment of the present invention. In the condensate water supply system, the condensate flow rate detection device 9
A condensate flow rate value determination device 25 that operates based on the detection signal of Or open control. Furthermore, the high-pressure drain pump inlet piping cold water injection valve 21 is fully opened by the high-pressure drain pump operation number determining device 24 and the high-pressure drain pump cold water injection system M23 when the number of high-pressure drain pumps 17 is in operation.

In this embodiment, similarly to the first embodiment, the high pressure drain pump 1
By ensuring the inlet pressure of 7, it is possible to prevent malfunction or pump trip of the high-pressure drain pump 17, and it is also possible to ensure the flow rate of water supply to the water supply pump 11.

FIG. 4 is a configuration diagram of a power generation plant according to a fourth embodiment of the present invention. The concept of high-pressure drain pump cold water injection is as follows.
Although it is the same as the embodiment, in order to further simplify the cold water injection system, only the high pressure drain pump inlet main pipe cold water injection valve 20 is used. The amount of cold water injected is equal to the number of pumps 17 in operation, or the number of pumps in operation and the number of standby bones injected. In this way, the causes of failure in the system are reduced, the necessary inlet pressure of the high-pressure drain pump 17 can be ensured, and a stable water supply to the steam generator 1 can be ensured.

FIG. 5 is a configuration diagram of a power generation plant according to a fifth embodiment of the present invention. The concept of high-pressure drain pump cold water injection is as follows.
Although it is the same as the embodiment, in order to further simplify the cold water injection system, only the high pressure drain pump inlet main pipe injection valve 20 is used, and a condensate flow rate value determination device 25 is installed, so that the condensate flow rate is rated condensate. When the flow rate reaches 50% or more, the high-pressure drain pump inlet main pipe cold water injection valve 20 is controlled to be fully open or open. In this way, the causes of failure in the system are reduced, the necessary inlet pressure of the high-pressure drain pump 17 can be ensured, and stable water supply to the steam generator 1 can be ensured.

〔Effect of the invention〕

According to the present invention, the following effects can be obtained by applying it to a condensate water supply system employing a feedwater heater drain pump in a steam motor plant such as an atomic coupler plant or a thermal power plant.

(a) Damage to the drain pump and tripping of the drain pump due to a flash phenomenon in the inlet piping of the high-pressure drain pump due to a drop in internal pressure of the high-pressure drain tank due to a sudden drop in plant output can be prevented. , the reliability of the condensate water supply system is improved.

(b) The required inlet pressure of the standby drain pump can be ensured in the event of a sudden drop in the output of the plant or a trip of the high-pressure drain pump, making it possible to supply stable water supply to the steam generator.

[Brief explanation of the drawing]

FIGS. 1, 2, 3, 4, and 5 illustrate the first embodiment of the present invention. Second. Third. 4th. A configuration diagram of a power generation plant according to a fifth embodiment, and FIG. 6 is a configuration diagram of a conventional power generation plant. 1... Steam generator, 3... High pressure turbine, 5... Low pressure turbine, 6... Turbine generator, 7... Condenser,
8... Condensate pump, 9... Condensate flow rate detection device, 1o...
-Low pressure water heater, 11... Water pump, 12... High pressure water heater, 13... Water supply flow meter, 14... High pressure drain tank. 16... High pressure drain pump inlet valve, 17... High pressure drain pump, 20... High pressure drain pump inlet main pipe cold water injection valve, 21... High pressure drain pump inlet piping cold water injection valve, 23... High pressure drain pump Cold water injection control device, 24.
- Device for determining the number of high-pressure drain pumps in operation, 25... Device for determining condensate flow rate value, 30... Inlet main pipe. Representative Patent Attorney Tadashi Akimoto No. 11! l Figure 2 Figure 3 Figure 4 Figure 5 61! l

Claims (1)

[Claims] 1. A steam generator, a high-pressure turbine into which the steam generated by the steam generator is introduced to perform work, and a low-pressure turbine into which exhaust steam from the high-pressure turbine is introduced to perform work; A condenser that returns the exhaust steam of the low-pressure turbine to water, a condensate pump that pressurizes and sends the condensed water in the condenser, and a condensate pump that is installed downstream of the condensate pump and heats the water supplied from the condensate pump. a low-pressure feed water heater, a water pump that pressurizes and sends water from the low-pressure feed water heater, and a water pump that receives pressurized water from the water pump and uses extracted steam from the high-pressure turbine to A steam motor equipped with a high-pressure feedwater heater that heats and returns the water to the steam generator, a drain tank that stores heated steam drain from the high-pressure feedwater heater, and a drain pump that pressurizes the drain and returns the drain to the water pump inlet. In the plant, a cold water pipe that returns part of the water supply from the low-pressure feed water heater to the inlet pipe of the drain pump, a cold water injection valve that adjusts the amount of cold water injected through the cold water pipe and returned to the inlet side of the drain pump; A steam motor plant characterized by comprising: a control device that controls the opening and closing of a cold water injection valve. 2. In claim 1, a plurality of the drain pumps are provided in parallel, the cold water injection valve is provided corresponding to the drain pump, and the control device controls each cold water injection according to the number of operating drain pumps. A steam motor plant, characterized in that it comprises means for controlling a valve. 3. The steam engine plant according to claim 1, wherein the control device controls a cold water injection valve according to a flow rate of condensate. 4. A steam generator, a high-pressure turbine into which the steam generated by the steam generator is introduced to perform work, a low-pressure turbine into which exhaust steam from the high-pressure turbine is introduced to perform work, and exhaust steam from the low-pressure turbine. a condenser that returns water to water, a condensate pump that pressurizes and sends condensate in the condenser, and a low-pressure feedwater heater that is installed downstream of the condensate pump and heats the water supplied from the condensate pump. , a water supply pump that pressurizes and sends water from the low-pressure water supply heater; and a steam generator that receives the supply of pressurized water from the water pump and heats the water with extracted steam from the high-pressure turbine. A drain-up system installed in a condensate water supply system of a steam power plant, comprising a high-pressure feedwater heater that returns the water to the water, the drain tank storing heated steam drain from the high-pressure feedwater heater; A drain pump system that includes a drain pump that returns a portion of the water supply from the low-pressure feed water heater to the inlet pipe of the drain pump; A drain-up system comprising: a cold water injection valve that adjusts the amount of cold water to be returned; and a control device that controls opening and closing of the cold water injection valve. 5. A control device installed in the drain up system according to claim 4, comprising means for detecting the flow rate of condensate and determining the control amount of the cold water injection valve according to the detected value. Control device. 6. A control device installed in the drain up system according to claim 4, which detects the number of operating drain pumps and controls the cold water injection valve according to the number of operating drain pumps, or according to the number of operating drain pumps and the number of standby pumps. A drain-up control device characterized by comprising means for performing. 7. Pressurize the water condensed in the condenser with a condensate pump and supply it to the low-pressure feed water heater.The water whose temperature has been raised in the low-pressure feed water heater is pressurized with the water supply pump and supply water to the high-pressure feed water heater. In the condensate water supply system that supplies feed water heated by the high pressure feed water heater to the steam generator, the drain of the high pressure feed water heater is pressurized by a drain pump and returned to the inlet of the water pump. A condensate water supply system, characterized in that a means is provided for pressurizing a portion of the water supplied from the low-pressure feed water heater back into the inlet pipe when the pressure inside the pump inlet pipe decreases and flushing occurs. . 8. In the drain-up system installed in the condensate water supply system of a steam engine plant, when the pressure in the drain tank of the high-pressure feed water heater changes suddenly, or when the load of the steam engine plant suddenly changes, or when the output of the steam generator A method for operating a drain pump, characterized in that when the water suddenly changes, a part of the water supply from the condensate system is returned to the inlet piping of the drain pump which returns the drain in the drain tank to the water supply pump inlet of the water supply system. 9. In the drain-up system installed in the condensate water supply system of a steam engine plant, when the pressure in the drain tank of the high-pressure feed water heater changes suddenly, or when the load of the steam engine plant changes suddenly, or when the output of the steam generator When the water suddenly changes, a part of the water supply from the condensate system is returned to the inlet pipe of the drain pump that returns the drain in the drain tank to the water supply pump inlet of the water supply system, and the pressure inside the inlet pipe is increased. A drain pump operating method characterized by ensuring a suction pressure of . 10. A steam generator, a high-pressure turbine into which the steam generated by the steam generator is introduced to perform work, and a low-pressure turbine into which exhaust steam from the high-pressure turbine is introduced to perform work;
A condenser that returns the exhaust steam of the low-pressure turbine to water, a condensate pump that pressurizes and sends the condensed water in the condenser, and a condensate pump that is installed downstream of the condensate pump and heats the water supplied from the condensate pump. a low-pressure feed water heater, a water pump that pressurizes and sends water from the low-pressure feed water heater, and a water pump that receives pressurized water from the water pump and uses extracted steam from the high-pressure turbine to A steam motor equipped with a high-pressure feedwater heater that heats and returns the water to the steam generator, a drain tank that stores heated steam drain from the high-pressure feedwater heater, and a drain pump that pressurizes the drain and returns the drain to the water pump inlet. In the plant,
A steam power plant, characterized in that a system is provided for constantly returning part of the cold water from the low-pressure feed water heater to the inlet pipe of the drain pump through a cold water pipe.