JP2575555B2 - Condenser - Google Patents

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 a condenser from an atmospheric environment when the plant is shut down.

[0002]

2. Description of the Related Art In recent years, a combined cycle power plant has been established as a power generation system that can realize both excellent load following performance and high thermal efficiency, and equipment has been developed to further refine these characteristics. Constant efforts are being made to improve. In terms of plant operation, operations that assume daily startup and shutdown from operation for base load,
In other words, it is a movement toward DSS (Dilly Start and Stop) operation, and the improvement of steam turbine system equipment is in line with this movement.

FIG. 5 shows a schematic system of a conventional combined cycle power plant. In FIG. 1, air pressurized by a compressor 1 is introduced into a combustor 2, and the gas burned here is introduced into a heat recovery boiler 4 after working in a gas turbine 3. A steam pipe 7 is disposed in the heat recovery boiler 4, and feed water pumps 5a, 5b,
The feed water pressurized at 5c is supplied with water through the steam drums 6a, 6b, 6c, and this water recovers the heat energy of the exhaust gas to become steam.

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

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

[0006] In this case, there is a problem that the inner surfaces of the steam pipes 7a, 7b and 7c in the exhaust heat recovery boiler 4 are corroded during operation. To suppress this corrosion, the oxygen concentration in the feedwater is limited to 80 ppb or less at startup. However, when the plant is started, the vacuum in the condenser 10 is broken, and the air flows into the condenser 10, so that the condensate comes into contact with the atmosphere, and a large amount of oxygen is dissolved in the condensate. The concentration becomes a high value of about 10,000 ppb from 7 ppb during normal operation, and this oxygen concentration is degassed by the condenser 10 of the conventional structure or degassed by the air extraction device 13 at startup. Then it will take too long.

[0007]

As means for solving the above-mentioned problems, there are an upper space having a tube bundle inside the main body side of the condenser 10 and a lower space accommodating a hot well for receiving and storing condensed condensed water. A partition pipe is connected between the two spaces with an openable and closable isolation valve to form a condensate passage condensed in the upper space. In this case, the upper space and lower space in the condenser are shut off by closing the isolation valve, 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, raise the vacuum in the upper space when starting the plant, 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 is opened and closed every day when the DSS operation is applied in earnest, and problems such as failure and damage occur compared to 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 be impossible to completely seal the upper and lower spaces, and air will be brought from the upper space to the lower space during plant shutdown, The dissolved oxygen concentration of the stored condensate increases, and the original purpose cannot be achieved. Therefore, it is necessary to disassemble the isolation valve at least once a year to inspect parts, and to take appropriate measures such as replacing parts before a problem occurs. In the event that the isolation valve is abnormal during operation of the plant or during shutdown of the plant that normally blocks the upper and lower spaces, urgent repair is required.

Generally, when mounting or removing 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. It is necessary to provide a slight clearance between the pipeline and the valve for smooth movement. After the valve is installed in the pipeline, it is necessary to eliminate this clearance. Therefore, in order to provide or eliminate clearance in the pipeline,
It is common to provide an expansion joint that can expand and contract in the pipe axis direction on one side of the valve. However, since this expansion joint expands and contracts in the axial direction, it applies an axial force to the pipe or valve after installation, and therefore requires extremely high sealing performance like the isolation valve targeted by the present invention. When used for such a valve, the valve may be deformed by the axial force and the sealing performance may be reduced. That is, it is considered that it is not preferable to apply the expansion joint to the connecting pipe in which the above-mentioned isolation valve is arranged.
SUMMARY OF THE INVENTION An object of the present invention is to provide a condenser in which an isolation valve can be easily attached and detached without an expansion joint in the middle of a communication pipe.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a condenser main body which receives a condensed condensate between an upper portion for accommodating a tube bundle for cooling and condensing the steam turbine exhaust gas. In a condenser, which is divided into a lower space for storing a hot well to be stored, and a communication pipe having an openable and closable isolation valve is arranged so as to communicate these upper and lower spaces, a part of the communication pipe is provided. Or, the whole is configured in an L shape, and both ends are formed in a flange structure,
One end is connected so as to communicate with the upper space of the condenser through an isolation valve, and the other end is connected so as to communicate with 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 has an L-shape, after disassembling the flange, the connecting pipe can be freely moved in both vertical and horizontal directions, 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 the communication pipe side, and thus can be easily removed. In addition, when it is not necessary to remove the isolation valve from the condenser main body as in the case of the inspection inside the isolation valve, it is possible to perform inspection using the space where the connecting pipe was located, while keeping it attached to the condenser main body. .

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

[0013]

FIG. 1 shows an embodiment of a condenser according to the present invention.
This will be described with reference to FIG. The same components as those of the conventional example shown in FIG. 5 are denoted by the same reference numerals, and description thereof is omitted.

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 while maintaining airtightness. A communication pipe 20 having an openable and closable isolation valve 21 is connected between the upper space A and the lower space B, and forms a sole passage for condensing water. Here, the connecting pipe 20 is formed in an L-shape, and one end is provided with a flange 2.
The other end is connected to the main body of the condenser 10 so as to communicate with the upper space A via the isolation valve 21 via the isolation valve 21 and to communicate with the lower space B via the flange 22b.

The disassembly procedure of the isolation valve 21 in the condenser configured as described above will be described with reference to FIGS. In disassembling, first, bolts 23a and 23b of 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 tightening the flange 22c connecting the isolation valve 21 and the upper space A is removed, and the isolation valve 21 is moved in the direction of the arrow Y in the figure and removed from the condenser main body. When the isolation valve 21 is attached, the isolation valve 21 can be easily attached by a procedure reverse to the above description. As described above, according to the present invention, maintenance work of the isolation valve 21 can be easily performed, and since there is no need to provide an expansion joint in the conduit of the communication pipe 20, excessive force is applied to the isolation valve 21. There is no need to damage the sheet part.

FIG. 4 shows another embodiment according to the present invention. In the present embodiment, the flange 22 and the flange 22c are connected by one bolt 23d with the isolation valve 21 interposed therebetween. Even in this case, the expansion joint is unnecessary, and the maintenance work of the isolation valve 21 can be easily performed.

[0017]

As is apparent from the above description, the present invention comprises a part or the entirety of a connecting pipe having an L-shape, both ends of which are formed in a flange structure, and one end of which is connected to a condenser through an isolation valve. The upper space and the other end are connected to the condenser main body so as to communicate with the lower space of the condenser, so that the isolation valve can be easily attached and detached without an expansion joint in the middle of the path. Thus, according to the present invention, disassembly of the isolation valve and
There is no danger of damaging the isolation valve when performing the inspection of parts, and there is an excellent effect that unnecessary troubles in maintenance and inspection can be avoided.

[Brief description of the drawings]

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

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

FIG. 3 is a view for explaining a procedure for disassembling the isolation valve of the condenser according to 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]

 DESCRIPTION OF SYMBOLS 10 ... Condenser 20 ... Connecting pipe 21 ... Isolation valve 22a, 22b, 22c ... Flange 23a, 23b, 23c ... Bolt

Claims (1)

(57) [Claims] The interior of the condenser body is divided into an upper space for accommodating a bundle of tubes for cooling and condensing the exhaust gas of the steam turbine, and a lower space for accommodating a hot well for receiving and storing the condensed condensate water. In a condenser in which a communication pipe having an openable and closable isolation valve is arranged so as to communicate these upper and lower spaces, a part or the whole of the communication pipe is formed in an L-shape, and both ends thereof are formed in a flange structure. And a condenser connected to the condenser body so that one end communicates with the upper space of the condenser through the isolation valve and the other end communicates with the lower space of the condenser. vessel.