JPH0545075A - Condenser - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a condenser in which an isolation valve can be easily attached and detached without interposing an expansion joint in the middle of the connecting pipe of the condenser. [Composition] The connecting pipe 20 is formed in an L shape. One end of the connecting pipe 20 is connected to the main body of the condenser 10 so that one end communicates with the upper space A through the isolation valve 21 by the flange 22a, and the other end communicates with the lower space B through the flange 22b. There is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine plant, and more particularly to a condenser capable of reliably isolating a hot well region in the condenser from the atmospheric environment when the plant is shut down.

[0002]

2. Description of the Related Art In recent years, combined cycle power plants have become well-established as a power generation system that can achieve both excellent load followability and high thermal efficiency. Constant efforts are being made to improve. In terms of plant operation method, operations that assume daily start and stop from operations for base load,
In other words, it is a move to DSS (Daily Start and Stop) operation, and the improvement of steam turbine equipment is in line with this move.

FIG. 5 shows a schematic system of a conventional combined cycle power plant. In the figure, the air pressurized by the compressor 1 is introduced into the combustor 2, and the gas combusted therein is introduced into the heat recovery boiler 4 after performing work in the gas turbine 3. A steam pipe 7 is arranged in the heat recovery boiler 4, and water supply pumps 5a, 5b,
Water supplied through the steam drums 6a, 6b, and 6c is supplied with pressure increased by 5c, and the water recovers the heat energy of the exhaust gas and becomes steam.

The steam from which the heat energy has been recovered is introduced into the steam turbines 8a, 8b, 8c, where it works, rotates the generator 9, and then is introduced into the condenser 10. A tube bundle 11 formed of a large number of cooling tubes is arranged in the condenser 10, and the steam that has worked in the steam turbines 8a, 8b, 8c is
It is condensed by the cooling water introduced into the cooling pipe, becomes condensed water, and falls into the hot well 12 for storage. The non-condensable gas contained in the steam in the condenser is released to the atmosphere by the air extraction device 13.

Condensate in the hot well 12 is condensed water pump 1
4 and is introduced into the gland steam condenser 15 where the gland leak steam extracted through the gland steam pipe 16 is condensed. Further, the condensate that has passed through the gland steam condenser 15 is sent to water supply pumps 5a, 5b, 5c, where it becomes high-pressure water and is sent to the exhaust heat recovery boiler 4 as described above. Further, a part of the condensate that has passed through the gland steam condenser 15 is sent to the condenser 10 via a valve 18 incorporated in the middle of the condensate circulation system pipe 17, and is circulated again in the condensate circulation system. ..

By the way, in this type, there is a problem that the inner surfaces of the steam pipes 7a, 7b, 7c in the exhaust heat recovery boiler 4 are corroded during operation. In order to suppress this corrosion, the oxygen concentration in the feed water is limited to 80 ppb or less at startup. However, when the plant is started up, the vacuum in the condenser 10 is broken, and the atmosphere flows into the condenser 10. Therefore, the condensed water comes into contact with the atmosphere, and a large amount of oxygen is dissolved in the condensed water. The concentration is as high as about 7 ppb during normal operation and about 10000 ppb, and this oxygen concentration is degassed by the condenser 10 of the conventional structure or by the air extractor 13 at startup. Then it will take too long.

[0007]

As means for solving the above-mentioned problems, an upper space having a tube bundle inside the main body of the condenser 10 and a lower space accommodating a hot well for receiving and storing condensed condensed water are provided. A partitioning member is used to keep confidentiality, and a partition pipe is connected between the two spaces with a connecting pipe having an openable and closable isolation valve to constitute a passage for condensate condensed in the upper space. In this case, the isolation valve is closed to shut off the upper and lower spaces in the condenser, and the vacuum in the lower space is maintained even after the vacuum in the upper space is broken. Store the dissolved oxygen concentration as it was during normal operation.When starting the plant, raise the vacuum in the upper space and then open the isolation valve to connect both spaces, and then guide the condensate from the lower space to the boiler. thing How to reduce the time for the condensate deaeration was necessary more conventionally it is considered.

By the way, the isolation valve attached to the condenser 10 has opening and closing operations every day when the DSS operation is applied in earnest, and causes problems such as breakdown and damage as compared with other components. It is expected to be easy to do. On the other hand, if the seat of the isolation valve is damaged, it will not be possible to completely seal the upper and lower spaces, and the atmosphere will be introduced from the upper space to the lower space during the plant shutdown, and The dissolved oxygen concentration of the stored condensate rises, and the original purpose cannot be achieved. Therefore, it is necessary to disassemble the isolation valve at least once a year to inspect the parts, and perform appropriate processing such as replacement of the parts before a problem occurs. In addition, if an abnormality is detected in the isolation valve during operation of the plant or when the plant that normally shuts off the upper and lower spaces is stopped, urgent repair is required.

Generally, when attaching or detaching a valve provided in the middle of such a pipeline, the valve is horizontally moved in the direction perpendicular to the axis of the pipeline. For smooth movement, it is necessary to provide a slight clearance between the pipe and the valve. It is also necessary to eliminate this clearance after the valve is installed in the pipeline. Therefore, in order to create or eliminate the clearance in the pipeline,
It is common to provide an expansion joint that can expand and contract in the axial direction of the conduit on one side of the valve. However, since this expansion joint expands and contracts in the axial direction, it exerts an axial force on the pipe or valve after installation, and therefore requires extremely high sealing performance like the isolation valve of the present invention. If used for a valve that is used, the valve may be deformed by an axial force and the sealing performance may be deteriorated. That is, it is considered unfavorable to apply the expansion joint to the connecting pipe in which the isolation valve is arranged.
Therefore, an object of the present invention is to provide a condenser in which an isolation valve can be easily attached and detached without interposing an expansion joint in the path of the connecting pipe.

[0010]

In order to achieve the above object, the present invention is directed to a space between upper portions for accommodating a tube bundle for cooling and condensing exhaust gas of a steam turbine in a condenser body, and for receiving condensed condensate. A part of a connecting pipe in a condenser which is divided into a lower space for accommodating hot wells to be stored and which is provided with a connecting pipe having an isolation valve that can be opened and closed so as to connect these upper and lower spaces. Alternatively, the whole structure is L-shaped and both ends are formed into a flange structure.
One end is connected to the upper space of the condenser via an isolation valve, and the other end is connected to the lower space of the condenser.

[0011]

In the present invention, since both ends of the connecting pipe have a flange structure, when removing the isolation valve, the flange is first disassembled, and then the connecting pipe is removed from the condenser main body. Here, since the connecting pipe is L-shaped, it can be freely moved in both the vertical and horizontal directions after the flange is disassembled, and can be removed very easily. Next, the isolation valve is removed from the condenser main body, but since the L-shaped communication pipe has already been removed, the isolation valve can be freely moved to this communication pipe side, and therefore can be easily removed. In addition, when it is not necessary to remove the isolation valve from the condenser body, such as when inspecting the inside of the isolation valve, it is possible to perform inspection using the space with the connecting pipe while it is still attached to the condenser body. ..

According to the present invention by the above method, the isolation valve can be very easily removed from the condenser body and inspected, and it is not necessary to install the expansion joint, which has been conventionally required. No excessive force is applied to the valve, and problems such as deterioration of sealing performance due to deformation of the valve do not occur.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a condenser according to the present invention will be described below with reference to FIG.
Or, it demonstrates with reference to FIG. It should be noted that the same components as those of the conventional example shown in FIG.

In FIG. 1, the inside of the main body of the condenser 10 is partitioned by a partition member 19 into an upper space A for accommodating the tube bundle 11 and a lower space B for accommodating the hot well 12 in an airtight manner. Between the upper space A and the lower space B, a connecting pipe 20 having a freely openable / closable isolation valve 21 is connected to serve as the only passage for condensing water. Here, the connecting pipe 20 is formed in an L-shape, and one end thereof has the flange 2
2a is connected to the main body of the condenser 10 so as to communicate with the upper space A through the isolation valve 21 and the other end is communicated with the lower space B through the flange 22b.

In the condenser thus constructed, the procedure for disassembling the isolation valve 21 will be described with reference to FIGS. 2 and 3. When disassembling, first, the bolts 23a and 23b of the flanges 22a and 22b are removed. Next, the L-shaped connecting pipe 20 is moved in the arrow X direction in the figure. Next, the bolt 23c that fastens the flange 22c that connects the isolation valve 21 and the upper space A is removed, the isolation valve 21 is moved in the direction of the arrow Y in the drawing, and is removed from the condenser main body. Further, when the isolation valve 21 is attached, it can be easily attached by the procedure reverse to the above description. As described above, according to the present invention, since maintenance work of the isolation valve 21 can be easily performed and it is not necessary to provide an expansion joint in the conduit of the communication pipe 20, excessive force is applied to the isolation valve 21. Moreover, it is not necessary to damage the seat portion or the like.

FIG. 4 shows another embodiment according to the present invention. In this embodiment, the flange 22 and the flange 22c are connected to each other across the isolation valve 21 with a single bolt 23d. Even in this case, the expansion joint is not necessary, and the maintenance and inspection work of the isolation valve 21 can be easily performed.

[0017]

As is apparent from the above description, according to the present invention, a part or the whole of the connecting pipe is formed in an L-shape, both ends thereof are formed into a flange structure, and one end of the connecting pipe is connected to the condenser via the isolation valve. Since the upper space and the other end are connected to the condenser body so as to communicate with the lower space of the condenser, the isolation valve can be easily attached and detached without interposing an expansion joint in the middle of the path. Therefore, according to the present invention, disassembly of the isolation valve,
There is no fear of damaging the isolation valve when the parts are inspected, and it is possible to avoid unnecessary troubles in maintenance and inspection.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a condenser according to the present invention.

FIG. 2 is a view for explaining the isolation valve disassembly procedure of the condenser of the present invention.

FIG. 3 is a view for explaining the isolation valve disassembly procedure of the condenser of the present invention.

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

FIG. 5 is a system diagram showing a system around a condenser of a steam turbine plant according to a conventional technique.

[Explanation of symbols]

 10 ... Condenser 20 ... Communication pipe 21 ... Isolation valve 22a, 22b, 22c ... Flange 23a, 23b, 23c ... Bolt

Claims (1)

[Claims] 1. A condenser main body is divided into an upper space for accommodating a tube bundle for cooling and condensing exhaust gas of a steam turbine and a lower space for accommodating a hot well for receiving and storing condensed condensate, In a condenser in which a connecting pipe having a freely openable / closable isolation valve is arranged so as to communicate these upper and lower spaces, a part or the whole of the connecting pipe is formed into an L-shape, and both ends thereof have a flange structure. Condensate characterized by being formed and connected to the condenser main body so that one end communicates with the upper space of the condenser via the isolation valve and the other end communicates with the lower space of the condenser. vessel.