JP4848386B2 - Power plant condensate system - Google Patents

Description

  The present invention relates to a condensate system in a power plant, and more particularly to a condensate system provided with a ground steam condenser and an air extractor condenser.

  In a power plant using a steam turbine, a condensate system is provided that supplies condensate obtained by condensing exhaust steam from the steam turbine to a steam generation source (reactor or boiler). Such a condensate system includes a condensate system having a ground steam condenser and an air extractor condenser.

  FIG. 5 schematically shows the configuration of such a condensate system as a conventional general example in the case of a nuclear power plant. The condensate system Tp in this example includes a condenser 1, a condensate pipe 2, a low pressure condensate pump 3, a condensate filtration device 4, a condensate demineralizer 5, an air extractor condenser 6, and a ground steam condenser. Includes water bottle 7.

  The condenser 1 condenses the exhaust steam from the steam turbine 8 through a path not shown in the figure to generate condensate. The condensate generated in the condenser 1 is fed to the high-pressure condensate pump (not shown) through the condensate pipe 2 while being boosted by the low-pressure condensate pump 3, and is boosted by the high-pressure condensate pump. The water is sent to a reactor outside the figure. During this time, the condensate flowing down the condensate pipe 2 undergoes treatment by the condensate filtration device 4 and the condensate demineralizer 5, undergoes heat exchange by the air extractor condenser 6, and further condenses the ground steam. Heat exchange is performed by the vessel 7.

  The air extractor condenser 6 functions to condense the steam used to extract air from the condensate flowing down the condensate pipe 2 and the accompanying steam from the condenser 1, and for that purpose, the condensate pipe Heat exchange with low-temperature condensate flowing down 2. On the other hand, the ground steam condenser 7 functions to condense the ground steam from the steam turbine 8 and the like into ground steam condensate, and for this purpose, heat exchange is performed with the low-temperature condensate flowing down the condensate pipe 2. Do. In FIG. 5, the ground steam is supplied to the ground steam condenser 7 through the ground steam return pipe 9 from the steam turbine 8.

  Such a condensate system Tp has a problem that water hammer occurs due to the air extractor condenser 6 and the ground steam condenser 7 when power is lost.

  FIG. 6 shows a mechanism of water hammer generation caused by the ground steam condenser 7. 6 corresponds to the portion surrounded by the square in FIG. 5, but the form of the drawing is changed for convenience of explanation.

  When a power loss occurs in the condensate system Tp, the power supply to the low-pressure condensate pump 3 and the high-pressure condensate pump is stopped, whereby the low-pressure condensate pump 3 and the high-pressure condensate pump are stopped. The condensate will stagnate inside. Even in such a state, the ground steam continues to flow into the ground steam condenser 7, and the condensate is heated in a stagnant state by the ground steam. For this reason, the temperature of stagnant condensate rises in the vicinity of the ground steam condenser 7.

  Here, the connection between the ground steam condenser 7 and the condensate pipe 2 is usually made by the vertical pipe portion 2v of the condensate pipe 2, and for this reason, the condensate pipe 2 is connected to the ground steam condenser 7. It has the horizontal pipe part 2h located in a spatially high position with respect to the ground steam condenser 7 on the upstream side. In such a condensate pipe 2, the high-temperature condensate 11 generated by heating by the ground steam condenser 7 rises up the vertical pipe portion 2v due to the difference in specific gravity, and reaches the horizontal pipe portion 2h. The horizontal tube portion 2h has a lower hydraulic head pressure than the vertical tube portion 2v. Therefore, the high-temperature condensate 11 that has reached the horizontal tube portion 2h may flash to become steam, and the steam pool 12 may be formed by the steam. When the steam pool 12 is formed, a water hammer may be generated if the steam pool 12 is brought into contact with the low-temperature condensate 13 to cause rapid condensation on the steam. The water hammer generation mechanism as described above also applies to the air extractor condenser 6 provided in the vertical pipe portion similar to the vertical pipe portion 2v.

  The above is the water hammer problem when power is lost. As a technique for solving such a water hammer problem, a technique disclosed in Patent Document 1 is known. Patent Document 1 discloses three methods. In the first method, a check valve is provided in the condensate piping, and the water hammer problem is solved by suppressing the rise of high-temperature condensate by the ground steam condenser, and the second method is provided with a head tank. The water hammer problem is solved by suppressing the high temperature condensate flush using the head pressure of the head tank, and the third method is to provide an emergency pump and supply cooling water to the condensate piping with this emergency pump. This eliminates the water hammer problem by reducing the high temperature condensate flush.

JP 7-260375 A

  Each of the methods disclosed in Patent Document 1 described above has a problem in practicality. That is, the first method has a problem in practicality because the system pressure loss increases due to the installation of the check valve and is not effective for the air extractor condenser, and the second and third methods. However, since additional installation of a head tank and an emergency pump and a cooling water supply pipe are required, there is a problem in practicality in terms of cost.

  For this reason, the current situation is that we have to rely on human resources to deal with the water hammer problem at the time of power loss, which increases the burden on the operator, and delays in response and errors in operation. Had the problem of not eliminating the possibility of human error.

  The present invention has been made in the background as described above. Regarding the condensate system of the power plant, the water hammer problem caused by the ground steam condenser and the air extractor condenser when the power is lost is systematized. The problem is to be able to solve the problem by the structure and to reduce the burden on the operator against the water hammer problem.

  In order to solve the above problems, in the present invention, steam generated by heating by a ground steam condenser in the condensate stagnated in the condensate pipe due to the stoppage of the condensate pump due to power loss, that is, steam caused by water hammer (condensate If the system is also equipped with an air extractor condenser, the steam generated by heating with the air extractor condenser is included in this. Can be solved. In this way, the water hammer problem can be solved by the system structure, and therefore, it can be handled substantially without relying on human hands, and additionally installed for the necessary system structure. The piping and equipment to be used can be completed within a practical range.

  The condensate system of the power plant according to the present invention based on the above idea is provided in the condensate pipe for feeding the condensate generated by the condenser to the steam generation source, and the condensate pipe for boosting the condensate. One of a water pump and a ground steam condenser and an air extractor condenser connected to the condensate pipe downstream from the condensate pump and exchanging heat with the condensate flowing down the condensate pipe Or a steam escape pipe is connected to the top of the bent part of the condensate pipe, and the condensate is recovered by the heat exchange in the ground steam condenser when the condensate pump is stopped due to power loss. The steam generated in the condensate stagnating in the pipe can be escaped from the condensate pipe by the steam escape pipe.

  For the condensate system as described above, it is preferable that an automatic stop valve is provided in the steam escape pipe so that the automatic stop valve can be opened by a power loss signal obtained for the power loss.

  By doing in this way, the steam escape by steam escape piping can be automated, and therefore it becomes possible to cope with the water hammer problem without relying on human labor at all, thereby further reducing the burden on the operator.

  Further, for the condensate system as described above, the condensate is taken out from the condensate pipe for cooling spray of the condenser, or the condensate is cooled from the condensate pipe to cool the low pressure turbine exhaust chamber. A low pressure turbine exhaust chamber spray pipe to be taken out for spraying is connected to the condensate pipe upstream of the ground steam condenser, and the attemperator spray pipe or the low pressure turbine exhaust chamber spray pipe is used as the steam escape pipe. Is preferable.

  By doing so, steam caused by water hammer can be released using the attenuator spray piping and low-pressure turbine exhaust chamber spray piping that are provided as normal piping in a general condensate system. Installation piping and equipment can be substantially unnecessary.

  As described above, it is preferable that steam escape can be automated even in the case of using the attemperator spray pipe and the low pressure turbine exhaust chamber spray pipe. For this purpose, an attemperator spray valve provided in the attemperator spray pipe is used. Alternatively, the exhaust chamber spray valve provided in the low-pressure turbine exhaust chamber spray pipe can be opened by a power loss signal obtained for the power loss.

  According to the present invention as described above, the water hammer problem caused by the ground steam condenser and the air extractor condenser at the time of power loss can be solved by the system structure, and therefore the water hammer problem is relied on manually. The operator's burden can be reduced.

  Hereinafter, modes for carrying out the present invention will be described. In addition, the condensate system of each embodiment demonstrated below is the same as that of the conventional condensate system Tp demonstrated regarding FIG. Therefore, the characteristic configuration of the condensate system of each embodiment will be described below, and the other configurations will be denoted by the same reference numerals as those in FIG. It shall be incorporated.

  FIG. 1 schematically shows the configuration of a condensate system 20 according to the first embodiment. The condensate system 20 of this embodiment is provided with a steam escape pipe 21. The steam escape pipe 21 is connected to the ground steam condenser 7 or the air extractor condensate in the condensate stagnated in the condensate pipe 2 due to the stoppage of the low pressure condensate pump 3 due to the water hammer cause steam, that is, the power loss of the condensate system 20. It functions to let steam generated by heating by the water condenser 6 escape from the condenser pipe 2 to the condenser 1. For this purpose, the steam escape pipe 21 is located at the top of the bent part of the condensate pipe 2 on the upstream side of the ground steam condenser 7, that is, immediately upstream of the vertical pipe part 2v to which the ground steam condenser 7 is connected (this is the air extraction). One end side is connected to the condensate pipe 2 at the horizontal pipe part 2h in the vertical pipe part to which the condenser condenser 6 is connected), and the other end side is connected to the condenser 1. Further, the steam release pipe 21 is provided with a stop valve 22, and when necessary, the stop valve 22 is opened so that steam can escape toward the condenser 1.

  In the condensate system 20 of the present embodiment, it is possible to cope with the water hammer problem only by additionally installing the steam escape pipe 21 without relying on human hands except for the operation of the stop valve 22 by the operator.

  FIG. 2 schematically shows the configuration of the condensate system 30 according to the second embodiment. The condensate system 30 of the present embodiment is basically the same as the condensate system 20 of the first embodiment, and an automatic stop valve 31 is provided in the steam escape pipe 21 instead of the stop valve 22 in the first embodiment. Is different. The automatic stop valve 31 receives a power loss signal 32 as an open command signal. Here, the power loss signal 32 is a signal obtained by detecting a power loss of the condensate system 30 that occurs as an in-house power loss or the like, more specifically, a power loss that will cause the low-pressure condensate pump 3 to stop. is there.

  In the condensate system 30 of this embodiment, the automatic stop valve 31 can be opened by the power loss signal 32. For this reason, it becomes possible to deal with the water hammer problem without relying on human labor at all, and the burden on the operator can be further reduced.

  FIG. 3 schematically shows the configuration of the condensate system 40 according to the third embodiment. In the condensate system 40 of this embodiment, the attenuator spray pipe 41 is assumed to have the same function as the steam escape pipe 21 in the first embodiment. The attenuator spray pipe 41 discharges a large amount of turbine bypass steam to the condenser 1 when starting or stopping the plant. The steam turbine 8 connected to the condenser 1 is protected from turbine bypass steam. That is, the temperator spray pipe 41 is a pipe element for taking out condensate from the condensate pipe 2 for cooling spray of the condenser 1, and is a pipe element normally provided in a condensate system of a general power plant. It is. In order to cause the attenuator spray pipe 41 to function in the same manner as the steam escape pipe 21, that is, to allow the water hammer-caused steam to escape from the condenser pipe 2 to the condenser 1, The hose is connected to the condensate pipe 2 in 2h, and the attenuator spray valve 42 of the attenuator spray pipe 41 is opened when necessary so that steam can escape to the condenser 1.

  In the condensate system 40 of this embodiment, water hammer-caused steam can be released by using an attenuator spray pipe 41 provided as a general pipe in a general condensate system, and an additional installation pipe Kind and equipment can be made substantially unnecessary.

  Here, in the case of the present embodiment, low pressure turbine exhaust chamber spray piping may be used instead of the attenuator spray piping 41. The low-pressure turbine exhaust chamber spray pipe is a pipe element that is used to extract condensate from the condensate pipe for cooling spray in the low-pressure turbine exhaust chamber. By using such a low-pressure turbine exhaust chamber spray pipe for escape of water hammer-caused steam, the same effect as in the case of using the attenuator spray pipe 41 can be obtained.

  FIG. 4 schematically shows the configuration of the condensate system 50 according to the fourth embodiment. The condensate system 50 according to the present embodiment is basically the same as the condensate system 40 according to the third embodiment, and the power loss signal 32 similar to that in the second embodiment is used as an open command signal for the attenuator spray valve. 42 is different in that it can be input to 42.

  In the condensate system 50 of this embodiment, the attenuator spray valve 42 can be opened by the power loss signal 32. For this reason, it becomes possible to deal with the water hammer problem without relying on human labor at all, and the burden on the operator can be further reduced. In the case of this embodiment, the low pressure turbine exhaust chamber spray pipe may be used instead of the attenuator spray pipe 41 as in the case of the third embodiment. However, when the low-pressure turbine exhaust chamber spray piping is used, the exhaust chamber spray valve can be controlled by the power loss signal.

  As mentioned above, although the form for implementing this invention was demonstrated, these are only representative examples, This invention can be implemented with various forms in the range which does not deviate from the meaning.

It is a figure which shows the structure of the condensate system by 1st Embodiment. It is a figure which shows the structure of the condensate system by 2nd Embodiment. It is a figure which shows the structure of the condensate system by 3rd Embodiment. It is a figure which shows the structure of the condensate system by 4th Embodiment. It is a figure which shows the structure of the conventional general condensate system in a nuclear power plant. It is a figure explaining water hammer generation.

Explanation of symbols

1 Condenser 2 Condensate Pipe 3 Condensate Pump 7 Grand Steam Condenser 20 Condensate System 21 Steam Relief Pipe 30 Condensate System 31 Automatic Stop Valve 32 Power Loss Signal 40 Condensate System 41 Attenuator Spray Pipe 42 Attenuator Spray valve 50 Condensate system

Claims (4)

A condensate pipe that feeds the condensate generated in the condenser to a steam generation source, a condensate pump provided in the condensate pipe, and connected to the condensate pipe downstream from the condensate pump, In a condensate system of a power plant comprising either or both of a ground steam condenser and an air extractor condenser that exchange heat with the condensate flowing down the condensate pipe,
A steam escape pipe is connected to the top of the bent part of the condensate pipe, and the condensate stagnated in the condensate pipe due to the heat exchange in the ground steam condenser when the condensate pump is stopped due to power loss. A steam condensate system for a power plant, wherein steam generated in the power plant can be escaped from the condensate pipe by the steam escape pipe.   The power generation according to claim 1, wherein an automatic stop valve is provided in the steam escape pipe, and the automatic stop valve can be opened by a power loss signal obtained for the power loss. Plant condensate system.   An attenuator spray pipe for taking out the condensate from the condensate pipe for cooling spray of the condenser, or a low-pressure turbine exhaust chamber spray pipe for taking out the condensate from the condensate pipe for cooling spray of the low-pressure turbine exhaust chamber. The attemperator spray pipe or the low-pressure turbine exhaust chamber spray pipe is used as the steam escape pipe so as to be connected to the condensate pipe upstream of the ground steam condenser. The condensate system of the power plant as described in 1.   The attenuator spray valve provided in the attenuator spray pipe or the exhaust chamber spray valve provided in the low-pressure turbine exhaust chamber spray pipe can be opened by a power loss signal obtained for the power loss. The condensate system of the power plant according to claim 3, wherein

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