JPH07151475A - Condenser - Google Patents

Abstract

PURPOSE:To disperse turbine bypass steam uniformly in a condenser and to introduce, cool down and condense the bypass steam of a large volume without impairing a condenser structure. CONSTITUTION:A plurality of bypass steam jet pipes 33a to 33d extending in parallel to the axis of a feed water heater 9 are provided, while jet holes in radial directions within prescribed angular ranges above and below a horizontal plane are provided only on the lateral sides opposite to the inner wall surface of a condenser, of the bypass steam jet pipes 33a and 33d which are disposed within the width of the area of projection in the substantially vertical direction of the feed water heater and at position nearest to the inner wall surface of the condenser. As for the other jet pipes 33b and 33c, the jet holes are formed on both of the upper and lower sides thereof, and baffle plates 38 are located above and below the parts wherein the jet holes are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface contact type condenser for condensing steam turbine exhaust of a steam turbine power plant, especially a nuclear power plant, and more particularly to improvement of a turbine bypass steam jet pipe section.

[0002]

2. Description of the Related Art Generally, in a surface contact type condenser in a steam turbine power plant, in addition to steam discharged from a turbine during normal operation, a power transmission system is used at the time of starting a boiler or a reactor or during plant operation. There is provided a means for introducing steam that bypasses the turbine to cool and condense it when the generator is cut off due to the accident.

By the way, in the case of an accident in the above-mentioned power transmission system, it is necessary to be able to immediately start power transmission after the accident is repaired, so that all of the turbine inflow steam amount during the plant rated operation can be bypassed. About one or two power plants with capacity are required for their operation. In this case, about twice the turbine displacement during normal operation is introduced into the condenser.

In the case of boiling water nuclear power generation, generally 10
It has a turbine bypass capacity of 0%, and in the case of pressurized water nuclear power generation, a turbine bypass capacity of 70-80% is required. Therefore, in order to provide a large-capacity turbine bypass facility, how effectively this large amount of turbine bypass steam is treated in the condenser is important.

FIG. 10 is a diagram showing a schematic system of a nuclear power plant. High-temperature, high-pressure steam generated from a steam generator 1 passes through a main steam pipe 2 and a steam control valve 3 and then a turbine 4
Is supplied to. The steam supplied to the turbine 4 performs work there and drives the generator 5, and the work steam is discharged to the condenser 6, where it is heat-exchanged with seawater flowing through the cooling pipe 7 and condensed and recovered. It becomes water. This condensate is boosted by the condensate pump 8 and sent to the low-pressure feed water heater 9, and the turbine 4
After being boosted by a water supply pump 11 driven by a water supply pump drive turbine 10 using bleed air from the above, it is returned to the steam generator 1 via a high pressure water supply heater 12.

On the other hand, the main steam pipe 2 and the condenser 6 are connected by the turbine bypass steam pipe 13 that bypasses the turbine 4. As described above, when a system accident occurs,
The main steam is discharged by the turbine bypass steam pipe 13 to the condenser 6 via the bypass valve 14 and the pressure reducing device 15.

By the way, FIG. 11 is a cross-sectional front view of a condenser 6 which is generally used in the past, and FIG. 12 is a side view of the condenser. The outer shell of the condenser 6 has an upper body barrel 6a and a lower body barrel 6b.
A cooling pipe group 17 composed of a large number of cooling pipes 16 is formed in the lower main body body 6b. That is, the water chambers 18 are provided on the left and right of the lower main body 6b.
a and 18b are provided, both ends of each cooling pipe 16 are communicated with the water chambers 18a and 18b, and the cooling water supplied to the water chamber 18a passes through the plurality of cooling pipes 16 as shown by the arrow 19. The cooling water flowing out to the chamber 18b and flowing through the cooling pipe 16 during that time exchanges heat with the exhaust flow 20 from the turbine that has flowed into the lower main body 6b through the upper main body 6a, and the exhaust from the turbine is condensed. , Condensed water is stored in the hot well 6c provided in the lower part of the lower body cylinder 6b.

In the upper body 6a, a low pressure feed water heater 9 extending in a direction orthogonal to the axis of the cooling pipe 16 is provided.
Also, an extraction pipe 21 connected to the low-pressure feed water heater 9 is provided.

On the other hand, a bypass steam jet pipe 22 connected to the turbine bypass steam pipe 13 is disposed below the feed water heater 9 in the upper main body body 6a. Then, the turbine bypass steam led to the turbine bypass steam pipe 13 is discharged from the bypass steam jet pipe 22 as shown in FIG.
As shown in FIG.
It exchanges heat with the cooling water flowing inside to condense and become condensed water.

FIG. 13 is a side view of the bypass steam jetting pipe 22 and FIG. 14 is a longitudinal sectional view thereof. A large number of jet holes 23 are formed in the upper surface and the lower surface of the bypass steam jetting pipe 22. Then, above and below the bypass steam jetting pipe 22, a large number of the jetting holes 23 are provided at positions separated from this.
A baffle plate 24 that faces the ejection hole 2 is provided.
The steam ejected from No. 3 does not directly collide with the adjacent member which is the condenser structure and damage it.

[0011]

However, as described above, when the bypass steam jetting pipe 22 is centrally provided in a part of the upper body case 6a to introduce the bypass steam into the condenser, the bypass steam is particularly If there is a lot of water, it is difficult for the bypass steam that has been intensively ejected to a part of the upper main body to flow uniformly into the entire condenser tube bundle, so the pressure near the ejection point may rise locally or the temperature may rise. As a result, there is a possibility that a member near the spouting point may be damaged. Further, the local introduction of bypass steam locally heats the steam turbine casing, which may cause deformation of the casing. This leads to increased turbine vibration,
This may cause damage to the turbine, which is not preferable.

Therefore, it may be considered to provide a large number of bypass steam injection pipes 22 and uniformly introduce the bypass steam into the entire condenser.

However, also in this case, the bypass steam jet pipe 2
It is necessary to provide a baffle plate 24 on the outside of 2 to protect the adjacent members such as the cooling pipe group 17, the feed water heater 9 and the extraction pipe 21. As a result, not only the internal structure and piping system in the condenser become complicated, but also the flow path of the turbine exhaust is obstructed, so that the condenser performance during normal operation is deteriorated.

It has also been proposed to dispose a bypass vapor injection pipe 22 between the cooling pipe group 17 and the hot well 6c. However, the introduction of a large amount of bypass steam increases the size of the bypass steam jet pipe 22 and requires the baffle plates 24 above and below, so that the position of the cooling pipe group 17 is raised to the upper part. become.

However, since the cooling water generally flows in the condenser, the cooling pipe group 17 is the heaviest.
If this is located above, the center of gravity rises upward, which is not desirable for earthquake resistance. Moreover, since a circulating water pipe for cooling water, a hot well outlet condensate pipe, etc. are installed in the lower part of the condenser adjacent to the lower condenser body 6b, there is interference with the bypass steam jet pipe. The larger the capacity, the more difficult it becomes to arrange.

Further, introducing the bypass steam only into the lower main body cylinder 6b is not suitable from the viewpoint of uniformly dispersing the bypass steam in the entire condenser, and further, the pressure in the lower main body cylinder 6b is extreme. There is also a problem that the water level of the hot well 6c fluctuates and the water level fluctuates. Further, there are many welding points between the baffle plate 24 and the bypass steam jetting pipe 22, and it is structurally difficult to remove the welding points and the work is difficult to perform, which causes a problem in terms of the strength of the welded structure.

In order to improve this, it is conceivable to enlarge the bypass steam injection pipe with a baffle plate, but this is not preferable because it increases the height of the condenser. Further, when the bypass steam is jetted, a large amount of steam is jetted from the jet hole 23 at a high speed when the bypass steam is jetted, so that vibration is likely to occur, and attaching a baffle plate to this requires sufficient strength of the welded portion, There is a problem that the structure becomes complicated and a sufficient welding length is not secured.

Further, it is proposed that the bypass steam jet pipe is provided with jet holes so that steam is jetted only on both sides in the horizontal direction. However, in a nuclear power plant having a large capacity bypass facility for a large capacity plant, Since there are three or four or more bypass steam introduction pipes per condenser, there is a space problem when trying to prevent the interference of the steam ejected from the adjacent bypass steam ejection pipes, and in the horizontal direction. If it is jetted out to, the jetted steam does not disperse, so there is a drawback that the jetted steam does not easily slow down immediately after jetting. Therefore, the bypass steam may collide with the adjacent structure inside the condenser at high speed and cause erosion or damage.

As described above, the method of using the bypass steam jet pipe having a large number of jet holes is very good for effectively dispersing the turbine bypass steam of the nuclear power plant in the condenser. A relatively large space is required to slow down the high-speed, high-energy turbine bypass steam that has been ejected. On the other hand, the bypass steam jetting pipe having the baffle plate can decelerate the bypass steam in a relatively narrow space, but there is a problem in terms of erosion and vibration.

In view of the above points, the present invention increases the overall size of the condenser, particularly height, without fear of impairing the cooling and condensing performance of the turbine exhaust steam during normal operation, which is the original purpose of the condenser. Condensate that can suppress the increase in size in the direction as much as possible, evenly disperse the turbine bypass steam in the condenser, and introduce a large volume of bypass steam without damaging the condenser structure to cool and condense it. The purpose is to obtain a vessel.

[0021]

The first invention of the present application is
In a surface contact type condenser having a plurality of feed water heaters provided in the upper main body body, a plurality of bypass steam jet pipes extending parallel to the axis of the feed water heater are provided, and the feed water heater is substantially vertical. The bypass steam injection pipe, which is arranged within the projected area width and is located closest to the inner wall surface of the condenser, has a predetermined upper and lower side of the horizontal plane only on the side surface facing the inner wall surface of the condenser. Radial ejection holes are provided within the angle range, and other bypass steam ejection pipes are formed with radial ejection holes on both upper and lower surfaces, and baffle plates are arranged above and below the ejection hole formation portion. Is characterized by.

A second invention is that each bypass steam jet pipe is
It is characterized in that it is arranged at substantially the same level between the cooling pipe group of the condenser and the feed water heater.

A third aspect of the invention is characterized in that the bypass steam jetting pipes are arranged above and below the cooling pipe group.

According to a fourth aspect of the invention, the bypass steam jetting pipe arranged below the cooling pipe group has jet holes formed on both upper and lower surfaces thereof, and baffle plates are provided above and below the jet hole forming portion. It is characterized by being arranged.

Further, in a fifth aspect of the invention, the turbine bypass system is provided with a plurality of bypass valves which are arranged in parallel with each other and open and close sequentially, and a turbine bypass pipe provided with a frequently used bypass valve, It is characterized in that it is connected to a bypass steam ejection pipe having ejection holes only on the side surface facing the inner wall surface of the condenser.

[0026]

[Operation] Even in a large-capacity nuclear power plant with large-capacity turbine bypass equipment, turbine bypass steam is jetted from the bypass steam jet pipe without baffle plate into a large space in the condenser through which the exhaust flow of the main turbine passes. On the other hand, in the bypass steam jet pipe with a baffle plate, the jetted turbine bypass steam collides with the baffle plate and is then discharged in the lateral direction, so it can be effectively decelerated in a narrow limited space. Can be condensed. Also,
By disposing the bypass steam injection pipe at a position where the main turbine exhaust flow during normal operation is not disturbed, pressure loss is not increased and good condenser performance is obtained.

[0027]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional side view showing an embodiment of the present invention, and FIG. 2 is a sectional front view showing two condensers 30,
30 is connected by a condenser connecting cylinder 31 and a feed pump driving turbine exhaust connecting pipe 32, and the condenser 30
A cooling pipe group 17 composed of a large number of cooling pipes 16 is provided inside, and four feed water heaters 9 are arranged in two rows above and below the cooling pipes 16 in parallel with the cooling pipes 16.

Between the cooling pipe group 17 and the feed water heater 9, four bypass steam jet pipes 33a are provided at substantially the same level.
33b, 33c and 33d are arranged parallel to the axis of the feed water heater 9.

By the way, the bypass steam ejection pipes closest to the inner wall surface of the condenser, that is, the bypass steam ejection pipes 33a and 33d on both outer sides of the four bypass steam ejection pipes are connected to the inner wall surface of the condenser. Radial ejection holes are formed in a predetermined angle range above and below the horizontal plane only on the opposite side surfaces, and the bypass steam ejection pipes 33a and 33d have projected area widths of the feed water heater 9 provided above them. It is arranged inside.

FIG. 3 shows the bypass steam jet pipe 33a,
..., 33d is an enlarged cross-sectional view of the bypass steam jet pipes 33a, 33b, 33c, 33d supported by a support device 34 provided in the condenser, and the bypass steam jet pipes 33a, 33d on both sides are supported. As described above, the radial ejection holes 35 are formed in the predetermined angle θ range only in the side surface facing the inner wall surface of the condenser, as described above (FIG. 3, FIG. 3). (Fig. 4). The predetermined angle θ is an angle at which the jetted steam does not directly contact the cooling pipe group 17 and the feed water heater 9 which are main structures in the condenser.

On the other hand, the intermediate bypass steam jet pipe 33b,
As shown in FIGS. 3 and 5, the 33c is provided with a large number of ejection holes 36 in the radial direction, avoiding the vicinity of the support device 34, only on the upper surface and the lower surface. The bypass steam jet pipe 3 is provided on the support rod 37, which also functions as a reinforcing member of the upper body of the condenser, at a position facing the upper and lower jet holes 36.
Baffle plate 38 so as to have a predetermined interval with 3b and 33c
Is welded. The support device 34 is provided with a slight clearance between it and the bypass steam jet pipes so as to allow thermal expansion of the bypass steam jet pipes 33a.

However, the bypass steam jet pipes 33a, 3
When the turbine bypass steam is supplied to 3d, the ejection hole 3
5 is sprayed in a radial direction toward the condenser inner wall over a range of a predetermined angle θ, merges with the main turbine exhaust flowing between the condenser inner wall surface and the feed water heater 9, and heats the cooling pipe 16. Condensed by replacement. On the other hand, the turbine bypass steam supplied to the bypass steam jet pipes 33b and 33c is
The baffle plate 3 is ejected vertically from the upper and lower ejection holes 36.
8 is decelerated by colliding with 8, and is deflected in the left and right directions so that the jet steam does not directly hit the feed water heater 9 and the like, merges with the main turbine exhaust and the like, and is condensed in the same manner as those.

FIG. 1 shows an example of a 1100 MWe class nuclear power plant having 100% turbine bypass equipment and two condensers 30. In this case, a turbine bypass valve having a nominal diameter of 9 inches is shown. 8 are required, and as shown in FIG. 6, each turbine bypass valve 14a, 1
Turbine bypass steam pipes 13 having 4b, ... 14h, respectively, are four condenser steam bypass pipes 3 of two condensers.
3a, 33b, 33c, 33d, respectively.

In the meantime, in the case of a nuclear power plant, the turbine bypass steam is introduced into the condenser at the time of starting / stopping the plant and at the time of a transient change such as a turbine load cutoff, which is a normal rating. It is generally not introduced during plant operation. Moreover, even if 100% load cutoff occurs, 10
The flow of 0% turbine bypass steam is limited to a very short time. FIG. 7 shows the change over time and the ratio of the amount of bypass steam flowing. As can be seen from FIG. 9, the steam flow rate becomes 50% or less about 10 seconds after the load interruption occurs.

The eight turbine bypass valves 14a, ...
In 14h, it is possible to deal with the change in the steam flow rate by sequentially changing from fully closed to fully open, but in this case, a large difference occurs in the operating time due to each turbine bypass valve. In other words, the valve used to start and stop the plant is 200 to 1000 hours during the life of the plant, but more than half of the turbine bypass valves are used for about 2 to 5 hours.
There is a big difference in the usage time.

Therefore, in the present invention, the turbine bypass valves 14a, 14b, 14c, 14d whose valve opening sequence is early.
Are sequentially provided on the turbine bypass steam pipes 13 connected to the outer bypass steam jet pipes 33a and 33d, and the valve opening order is set to the turbine bypass steam pipes 13 connected to the intermediate bypass steam jet pipes 33b and 33c. Slow turbine bypass valves 14e, 14f, 14g, 14h are sequentially provided.

However, the bypass steam injection pipes 33b and 33c with the baffle plate are used only for a comparatively short time, and the erosion of the baffle plate and the fatigue of the welded portion of the baffle plate and the supporting device 34 are caused. Therefore, it is very advantageous and the reliability can be improved.

Since the present embodiment is configured as described above, it is possible to dispose the turbine bypass steam jet pipe between the condenser tube bundle and the feed water heater so as not to disturb the flow of the main turbine exhaust steam. A large capacity turbine bypass facility can be installed without increasing the pressure loss in the upper part of the condenser. In addition, by combining the bypass steam jet pipe without baffle plate and the bypass steam jet pipe with baffle plate, the jet pipe can be placed in a limited space, and a large capacity turbine bypass facility can be used even when the number of condensers is small. Is possible.

8 and 9 are a sectional side view and a sectional front view showing another embodiment of the present invention. Above the cooling pipe group 17, a condenser inner wall similar to that of the first embodiment is provided. Bypass steam ejection pipes 33a, 33d having ejection holes only on the opposite surfaces
The bypass steam jetting pipes 33b and 33c having the baffle plates 38 on the upper and lower sides are arranged below the cooling pipe group 17. The bypass steam jet pipes 33a and 33d which do not require the baffle plate 38 are arranged substantially directly below the feed water heater 9 in the longitudinal direction so as not to disturb the flow of the exhaust steam of the main turbine.

However, also in this case, the steam ejected from the bypass steam ejecting pipes 33a and 33d is ejected at an end divergence angle so as not to directly hit the feed water heater 9 and the cooling pipe group 17, and thereby, in the condenser. The high-speed bypass steam ejected to the steam generator will not hit the main structure in the condenser before it slows down and weakens the energy.

In the condenser of a large capacity nuclear power plant, the exhaust steam of the steam turbine for driving the reactor feed water pump is guided between the cooling pipe group 17 and the hot well 6c in the lower part of the condenser, and the condensed steam is condensed into the condenser. A space for disperse the steam into the bypass steam jet pipes 33b, 33 having a baffle plate which is rarely used during normal operation in this limited portion.
Since c is provided, it is possible to suppress an increase in the external dimensions of the condenser.

Further, even when the turbine bypass steam is large, the turbine bypass steam is introduced by being dispersed in the upper part and the lower part of the condenser cooling pipe group, so that the turbine bypass steam is dispersed in the entire condenser, and The soundness of the structure of the condenser is secured without the occurrence of locally high pressure part or the local heating. Also, instead of introducing a large-capacity turbine bypass steam into one location, it is preferable to disperse it into each location of the condenser and introduce it into the condenser, in terms of energy distribution, and the performance of the condenser is not considered. Is also preferable.

In this embodiment, the bypass steam jet pipes are dispersed to introduce the jet pipes into the upper body barrel and the lower body barrel of the condenser, but other portions, for example, condenser connection are shown. It can also be installed on the body. Further, although the baffle plate is shown as being independent of the ejection pipe, an integral one may be used.

[0045]

As described above, according to the present invention, a plurality of bypass steam ejecting pipes extending in parallel with the axis of the feed water heater are provided, and the bypass steam jet pipes are arranged within a substantially vertical projection area width of the feed water heater. In the bypass steam jet pipe arranged closest to the inner wall surface of the condenser, only the side surface facing the inner wall surface of the condenser has a radial direction within a predetermined angle range above and below the horizontal plane. Since the ejection holes are provided, the steam ejected from the ejection holes does not directly hit the feed water heater, the cooling pipe group, etc., and other bypass steam ejection pipes have radial ejection holes on the top and bottom surfaces. However, since baffle plates are provided above and below the ejection hole forming portion, the steam ejected from the ejection holes collides with the baffle plate, is decelerated, and then flows to the left and right. Limited and not disturbing Even allowing large turbine bypass facility when effectively condenser radix can disposed the bypass steam jet pipe is small pace.

Therefore, even in a large capacity turbine bypass facility of a large capacity nuclear power plant, the condenser can be economically excellent and have good performance and reliability.

[Brief description of drawings]

FIG. 1 is a sectional side view of a condenser of the present invention.

FIG. 2 is a sectional front view of the same.

FIG. 3 is a vertical cross-sectional view of a bypass steam ejection pipe section.

FIG. 4 is a side view of an outer bypass steam ejection pipe.

FIG. 5 is a side view of a bypass steam ejection pipe in the middle portion.

FIG. 6 is a diagram illustrating a configuration of a bypass steam pipe section.

FIG. 7 is a bypass vapor amount change diagram.

FIG. 8 is a sectional side view of another embodiment of the present invention.

FIG. 9 is a sectional front view of the same.

FIG. 10 is a schematic system diagram of a steam turbine plant.

FIG. 11 is a sectional front view of a conventional condenser.

FIG. 12 is a sectional side view of the same.

FIG. 13 is a side view of a bypass steam jet pipe.

FIG. 14 is a vertical sectional view of a bypass steam jet pipe.

[Explanation of Codes] 6, 30 Condenser 9 Feed Water Heater 13 Turbine Bypass Steam Pipe 14 Bypass Valve 16 Cooling Pipe 17 Cooling Pipe Group 33a, 33b, 33c, 33d Bypass Steam Jet Pipe 35, 36 Jet Hole 38 Baffle Plate

Claims (5)

[Claims] 1. A surface contact type condenser in which a plurality of feed water heaters are provided in an upper main body cylinder, wherein a plurality of bypass steam jet pipes extending parallel to an axis of the feed water heater are provided and the feed water heating is performed. The bypass steam jet pipe, which is disposed within the projected area width in the substantially vertical direction of the condenser, is disposed at the position closest to the inner wall surface of the condenser, only on the side surface facing the inner wall surface of the condenser, Radial ejection holes are provided within a predetermined angle range above and below the horizontal plane, and other bypass vapor ejection pipes are formed with radial ejection holes on both the upper and lower sides, and baffle plates are provided above and below the ejection hole forming portion. A condenser characterized by being provided with. 2. The condenser according to claim 1, wherein each of the bypass steam jetting pipes is arranged at substantially the same level between the cooling pipe group of the condenser and the feed water heater. . 3. The condenser according to claim 1, wherein the bypass steam jetting pipes are arranged above and below the cooling pipe group. 4. A bypass steam jet pipe arranged below the cooling pipe group has jet holes formed on both upper and lower surfaces thereof, and baffle plates are provided above and below the jet hole forming portion. The condenser according to claim 1, wherein the condenser is provided. 5. The turbine bypass system is provided with a plurality of bypass valves which are arranged in parallel with each other and open and close sequentially, and a turbine bypass pipe provided with a frequently used bypass valve is an inner wall surface of a condenser. The condenser according to claim 1, wherein the condenser is connected to a bypass steam ejecting pipe having an ejection hole only on a side surface opposed to.