JPH042841B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a drain system clean-up device for a steam turbine plant, and in particular, the present invention relates to a drain system clean-up device for a steam turbine plant, and in particular, it cleans up impurities such as rust and dirt accumulated in the drain system to generate steam. This invention relates to a drain system cleanup device for a steam turbine plant that prevents water from flowing into the drain system.

(Prior Art) Generally, a steam turbine is configured to collect condensate of a steam turbine or drain from a feed water heater built into a water supply system in a drain tank, and return this drain to the condensate system using a drain pump. The plant is known.

FIG. 5 shows the configuration of this type of conventional steam turbine plant, in which steam generated in a steam generator 1 such as a boiler or a nuclear reactor is sent to a high-pressure turbine 3 through a steam control valve 2 and drives an output shaft 4. do.
The steam that has done work here is sent to the low pressure turbine 5, drives the output shaft 4, and is then sent to the condenser 6. Note that a generator 7 is connected to the output shaft 4 to generate electric power. The steam sent to the condenser 6 is cooled and condensed here to become condensed water. This condensate is extracted via a condensate pump 8, passed through a condensate purifier 9, a low-pressure feedwater heater 10, a feedwater pump 11, and a high-pressure feedwater heater 12 in order to be heated and sent to the steam generator 1. Note that a part of the steam that has done work in the low-pressure turbine 5 and high-pressure turbine 3 is sent to the low-pressure feedwater heater 10 and the high-pressure feedwater heater 12, respectively, to heat the condensate.

In addition, the steam drain that exchanged heat with the feed water in the high-pressure feed water heater 12 is collected in the drain tank 15,
Thereafter, it is extracted by the drain pump 16 and sent to the suction side of the water supply pump 11.

In such a conventional steam turbine plant,
Before driving the turbine plant, from the condenser 6 to the condensate pump 8, the condensate purification device 9, and the low pressure feed water heater 1
0. Clean-up to purify the inside of the condensate system connected to the feed water pump ₁₁ via valve V ₁ and the water supply system connected from the feed water pump 11 to the steam generator 1 via valve V 2 , high pressure feed water heater 12, and valve V ₃ . Drive. For clean-up operation, valves V ₁ , V ₂ ,
Block V ₃ and stop the water supply pump 11.
The condensate pump 8 is driven, and purified water is sent to the condenser 6 via the condensate purifier 9, the low-pressure feed water heater 10, the bypass line 18 of the feed water pump 11, the high-pressure feed water heater 12, and the purification line 19. The water is circulated through the water purification system connected to the water supply. Note that the valve 20 of the bypass line 18
The valve 21 of the purification conduit 19 is opened during the clean-up operation and closed during normal operation.

(Problems to be Solved by the Invention) However, in this type of conventional steam turbine plant, although it is possible to purify the inside of the condensate and water supply system before starting up the turbine plant, the drain tank 15 and the drain It is not possible to purify the drain system connected to the suction side of the water supply pump 11 via the pump 16.

Therefore, rust that accumulates in the above drain system,
There was a risk that dust and the like would flow into the steam generator 1 when the turbine plant was started up and damage internal equipment.

In addition, nuclear power plants have had the problem of high levels of radioactivity within the turbine plants, resulting in increased radiation exposure for workers during maintenance and inspections.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a drain system for a steam turbine plant that eliminates the problems of the conventional techniques described above and that can purify impurities such as rust and dirt accumulated in the drain system before starting the steam turbine plant. Our objective is to provide a cleanup device.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention collects condensate and at least one of the drains of the feed water heater incorporated in the water supply system in a drain tank, and collects this drain into a drain tank. In a steam turbine plant in which condensate is returned to the condensate system by a pump, a condensate purification pipe is branched from the downstream side of a condensate purification device incorporated in the condensate system and connected to the drain tank. However, an on-off valve that is normally closed is installed in the middle of the pipeline, and this on-off valve is opened during clean-up operation of the turbine plant to enable clean-up in the drain system.

(Function) To explain the function based on the above-mentioned configuration, when the on-off valve built in the drain system purification pipe is opened during clean-up operation before the start-up of the steam turbine plant, the purified water flows out. The water flows into the drain tank through the drain system purification pipe, and is further extracted by the drain pump and flows into the condensate system. As a result, impurities such as rust and dirt that remain in the drain system are removed, and the impurities that have flowed into the condensate system are transferred to the water supply purification system that cleans up the condensate and water supply systems. The water enters the water, passes through a condenser, and is purified by a condensate purification device.

(Example) The first example of the drain system cleanup device for a steam turbine plant according to the present invention will be described below.
This will be explained with reference to the figures. Note that the same parts as in FIG. 5 are given the same reference numerals, and the explanation thereof will be omitted.

In FIG. 1, according to the present embodiment, a drain system purification pipe 2 is connected between a condensate purification device 9 connected to the discharge side of a condensate pump 8 and a low pressure feed water heater 10.
5 is branched, and this drain system purification pipe 25 is connected to the drain tank 15 via an on-off valve 26 in the middle. Furthermore, a valve _V4 , which is normally open, is connected downstream from the branched position of the drain system purification pipe 25.

In the turbine plant configured in this manner, the interior of the condensate and water supply systems described above as well as the interior of the drain system can be purified before starting up the turbine plant.

During clean-up operation before startup of the turbine plant, the on-off valve 26 and valves 20 and 21 are opened, valves V ₁ , V ₂ and V ₃ are closed, and the condensate pump 8 and drain pump 16 are driven. . Note that in this case, the water supply pump 11 is stopped. Then, the purified water stored in the condenser 6 is extracted by the condensate pump 8 and sent to the condensate purifier 9, where it is purified. After that, the purified water is sent to the low pressure feed water heater 1.
0, returns to the condenser 6 via the bypass pipe 18, high-pressure feed water heater 12, and purification pipe 19, and circulates through the feed water purification system to purify impurities such as rust and dirt.At the same time, it is purified. Water is drain system purification pipe 2
5. It passes through the on-off valve 26 and is sent into the drain tank 15, extracted by the drain pump 16, and sent downstream of the low-pressure feed water heater 10. The purified water, which has been purified from impurities such as rust and dirt in the drain system, is circulated within the water supply and digestion system and sent to the condensate purification device 9 connected to the discharge side of the condensate pump 8, where it is be purified.

As described above, according to this embodiment, since the condensate and water supply systems can be purified and the drain system can be purified simultaneously, rust, dirt, etc. can be removed from the steam generator 1 when the turbine plant is started. There will be no inflow. It should be noted that if the valve ₄ is closed when purifying the inside of the drain system, only the drain system and the water supply system will be purified.

FIG. 2 shows a second embodiment of the drain system cleanup device for a steam turbine plant according to the present invention, and shows a drain pump 16 in the drain system.
A valve 31 is incorporated in the discharge side pipe 30, and a drain system circulation pipe 32 is connected upstream of the valve 31. Further, this drain system circulation pipe 32 is connected to the condenser 6, and a valve 34 is installed in the middle thereof.

According to this embodiment, when the valve 31 is closed and the valve 34 is opened during clean-up operation, the purified water that has purified rust, dirt, etc. in the drain system is directly sent to the condenser 6 and circulated. , it is possible to efficiently purify the inside of the drain system.

Further, FIG. 3 shows a third embodiment of the drain system cleanup device for a steam turbine plant according to the present invention. is collected in the drain tank 35. Thereafter, the drain extracted by the drain pump 36 is sent to the suction side of the high pressure condensate pump 37.

Even in a steam turbine plant configured in this manner, during clean-up operation of the turbine plant, it is possible to purify the inside of the condensate water system and the water supply system as well as the inside of the drain system.

FIG. 4 shows a fourth embodiment of the drain system cleanup device for a steam turbine plant according to the present invention. According to this embodiment, two drain system cleaning pipes 25a, 25b is branched, and one drain system purification pipe 25a is connected to the drain tank 15 of the high-pressure feed water heater 12 via an on-off valve 26a. Further, the other drain system purification pipe 25b is connected to the drain tank 35 of the low pressure feed water heater 10 via an on-off valve 26b.

With this configuration, by opening both the on-off valves 26a, 26b during clean-up operation, the low-pressure and high-pressure feed water heaters 10, 1
Two drain systems can be purified at the same time.

〔Effect of the invention〕

Since the configuration is as described above, according to the present invention,
When performing a clean-up operation before starting up a steam turbine plant, the drain system can be purified at the same time as the conventional condensate and water supply systems are purified.

Therefore, rust, dirt, etc. that remain in the drain system do not flow into the steam generator when the turbine plant is started, and damage to internal equipment can be prevented.

Furthermore, in nuclear turbine plants, the level of radioactivity within the plant can be kept low, and workers can be prevented from being exposed to radiation during maintenance and inspections.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing a first embodiment of a drain system cleanup device for a steam turbine plant according to the present invention, FIG. 2 is a system diagram showing a second embodiment of the same cleanup device, and FIG. 3 is a system diagram showing a second embodiment of the same cleanup device. FIG. 4 is a system diagram showing a third embodiment of the cleanup device, FIG. 4 is a system diagram showing a fourth embodiment of the cleanup device, and FIG. 5 is a system diagram of a conventional steam turbine plant. 1... Steam generator, 6... Condenser, 8... Condensate pump, 9... Condensate purification device, 10... Low pressure feed water heater, 11... Water feed pump, 12... High pressure feed water heater , 15, 35...Drain tank, 16, 3
6...Drain pump, 19...Purification pipe, 2
5, 25a, 25b... Drain system purification pipe, 2
6, 26a, 26b...Opening/closing valve, 32...Drain system circulation pipe,...Condensate system,...Water supply system,
...Water purification system, ...Drain system, ₁ to ₄ ...Valves.

Claims (1)

[Claims] 1. In the above turbine plant, the drain of at least one of the condensate and the feedwater heater incorporated in the water supply system is collected in a drain tank, and this drain is returned to the condensate system by a drain pump, wherein the condensate system A drain system purification pipe was branched from the downstream side of the condensate purification device built into the tank and connected to the drain tank, and an on-off valve that was normally closed was built in the middle of the pipe. A drain system cleanup device for a turbine plant as described above.