JPS61149707A - Moisture separating reheater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a moisture separator reheater.

[Technical background of the invention and its problems] In general, in nuclear power plants that use light water, such as boiling water reactors or pressurized water reactors, the steam sent to the steam turbine is the same as in thermal power plants that use fossil fuels. This is so-called wet steam, which has much more moisture than steam. Moisture in this wet steam not only erodes the blades of the steam turbine, but also reduces the efficiency of the steam turbine, so it must be removed during the cycle.

Therefore, in nuclear power plants, a moisture separator in the form of a corrugated plate with a chevron-type drain pot, for example, is installed between the high-pressure turbine and the low-pressure turbine, and the moisture separator is installed between the high-pressure turbine and the low-pressure turbine. Efforts are being made to reduce this to 1% or less.

Furthermore, if a reheat cycle is adopted in which this steam with reduced moisture content is heated in a reheating device that uses steam generated in a nuclear reactor or steam generator as a heat source, and the heated steam is supplied to a low-pressure turbine, low-pressure This not only contributes to improving the efficiency of the turbine, but also alleviates erosion of the low-pressure turbine caused by wet steam.

Generally, the moisture separator and reheat device are housed in one housing and are referred to as a moisture separator and reheater.

Conventionally, this type of reheating device used can be roughly divided into a one-stage reheating type and a two-stage reheating type.

The one-stage reheating type is a type in which reheating is performed using steam generated in a nuclear reactor or a steam generator. On the other hand, in the two-stage reheating method, extracted steam from the high-pressure turbine is used to reheat the first stage, and steam generated in the reactor or steam generator is used to reheat the second stage.
This is a type of reheating stage. All of these reheating devices are cross-flow type shell-and-tube heat exchangers in which reheated steam from a heating source flows into heat transfer tubes, and cycle steam to be reheated flows outside the heat transfer tubes.

Figure 9 shows the main steam pipe system around the turbine and moisture separator reheater of a conventional general reheat nuclear power plant. The steam pipe 1 leads to a high-pressure turbine 2 , and the steam that has worked within the high-pressure turbine 2 is led into the body shell 4 of a moisture separator reheater 6 by a cross-around inlet pipe 3 .

Moisture is removed from the cycle steam within the main body shell 4, and it is further heated by heat exchange with a heating steam system (not shown), becoming heated steam and passing through the cross-around outlet pipe 5 to the low-pressure turbine 6.
flow into.

In such a system, the steam flowing through the cycle is heated in the moisture separator reheater 7, so that the temperature of the cross-around outlet pipe 5 is higher than the temperature of the cross-around inlet pipe 3, and the temperature difference is up to 120 It can even reach ℃. In addition, the moisture separation reheater 7 is often placed near the low-pressure turbine 6, and the length of the cross-around inlet pipe 3 is longer than that of the cross-around outlet pipe 5. Tube 5 is said to be larger.

Considering the thermal deformation behavior of an operating plant based on these conditions, the following becomes clear.

FIG. 10 shows the thermal deformation behavior, where the broken line shows the state before deformation and the solid line shows the state after deformation.

As is clear from the figure, when the moisture separator reheater 7 is not fixed and the free thermal expansion of the cross-around inlet pipe 3, the cross-around outlet pipe 5 and the equipment is not restricted, the moisture separator reheater 7 produces a large displacement in the horizontal plane. This is because thermal expansion of the cross-around inlet pipe 3 causes displacement in the X and Y directions in the horizontal plane, and furthermore, the cross-around outlet pipe 5, which is higher in temperature and has higher rigidity,
The results of elongation in the Y2 direction overlap, and the maximum displacement is extremely large. This large amount of displacement becomes a constraint on the support method of the moisture separation reheater 7, and if the deformation is restrained, the stress in the cross-around inlet pipe 3 and the cross-around outlet pipe 5 will become excessive, and as a result, the moisture separation reheater It is known that excessive force is applied to the piping attachment portion between the vessel 7 and the turbine.

FIG. 11 shows an example of a thermal deformation analysis result including the cross-around inlet pipe 3 and the cross-around outlet pipe 5 of the moisture separation reheater 7. In the figure, the cross-around inlet pipe 3 is connected to the lower side of the main body WA4 of the moisture separation reheat I17, while the cross-around outlet pipe 5 is connected to the upper side.

In addition, in the figure, the solid line indicates the position when installed.
The broken line indicates the position after thermal deformation.

On the other hand, conventional domestic boiling water power plants have adopted a non-reheat cycle, which requires a large moisture separator and reheater.
was not required, and instead a relatively small moisture separator was used and suspended from a beam.

This method can also be applied to the moisture separator reheater 7, but in general, the moisture separator reheater 7 has large restrictions on support points due to its size, and requires the use of beams for hanging. Location imposes major constraints on building design. In addition, the hanging method requires a building structure above the moisture separation reheater 7, which has many disadvantages from the viewpoint of construction cost and earthquake resistance. A floor-standing system is being considered as a support system for the vessel 7.

FIG. 12 shows a conventional general heat exchanger, for example, a single-floor support method for a feed water heater 9. In the figure, reference numeral 10 indicates a main body shell having a water chamber 11 on the side. .

Both sides of this main body trunk 10 are supported by 1111111a, 111
), and the support leg 11a on the right side of the figure and the support leg 11b on the left side in the figure have different configurations.

That is, in the support leg 11a on the right side of the figure, a hole 14 slightly larger than the diameter of the foundation bolt 13 is bored in the bottom plate 12, as shown in FIGS. 13 and 14, and the foundation bolt 13 is inserted into this hole 14. It is securely fixed by a nut 15.

On the other hand, as shown in FIGS. 15 and 16, the left support leg 11b has an elongated hole 16 into which the foundation bolt 13 is inserted. It is said that it is possible to follow.

The floor-mounted moisture separator reheater is already in use in pressurized water nuclear power plants.

However, in such a pressurized water type nuclear power plant, it is possible to use an expansion joint, that is, an expansion, in the cross-around inlet pipe 3 and the cross-around outlet pipe 5, so that the thermal expansion of the cross-around inlet pipe 3 and the cross-around outlet pipe 5 is reduced. can be absorbed by expansion, and how it is supported does not really matter.

That is, in general, the support of a pressurized water type moisture separator reheater only needs to release the thermal expansion of the device itself, and there is no need to accommodate the *m movements shown in FIG. 10 or FIG. 11. Therefore, in the case of the pressurized water type, it is sufficient to support the moisture separation reheater by using the conventional support legs 11b having a simple sliding surface.

On the other hand, in the case of a boiling water nuclear power plant, it is not preferable to use expansions in the cross-around inlet pipe 3 and the cross-around outlet pipe 5 from the viewpoint of improving reliability in order to prevent leakage of radioactive cycle steam. .

For this reason, in a moisture separator reheater for a boiling water power generation plant, the support leg 11b has a simple sliding surface like a moisture separator reheater for a pressurized water power generation plant or a conventional heat exchanger.
Therefore, it is necessary to use a supporting method that allows the amount of displacement without fixing the equipment.

[Object of the Invention] The present invention has been developed in response to such conventional circumstances,
We provide a moisture separation reheater that can absorb the displacement caused by thermal expansion of the cross-around inlet pipe and cross-around outlet pipe, and effectively eliminate the thermal stress generated in the cross-around inlet pipe, cross-around outlet pipe, and body shell. This is what we are trying to provide.

[Summary of the Invention] That is, the present invention provides a system in which a cross-around inlet pipe connected to a high-pressure turbine and a cross-around outlet pipe connected to a low-pressure turbine are directly connected to a main body shell, and the main body shell is supported on a floor by a plurality of support legs. The moisture separating reheater is supported by a moisture separating reheater, characterized in that the supporting legs are placed on a floor surface via a rolling mechanism.

[Embodiment 1 of the Invention] The details of the present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 shows an embodiment of the moisture separation reheater of the present invention, in which reference numeral 4 indicates a cross-around inlet pipe 3 connected to a high-pressure turbine 2 and a cross-around outlet connected to a low-pressure turbine 6. It shows the main body to which the pipe 5 is directly connected. Support legs 17 are provided at the bottom of both ends of the main body trunk 4.
is located. The support leg 17 is placed on a floor surface 19 via a rolling mechanism 18. The rolling 1118 is constituted by rotary casters 20 that are rotatable. The rotary leg wheels 20 are rotatable at a portion where they are attached to the support legs 17 and the bottom plate 21, and the wheels 22 are also rotatable. Note that the number of rotary casters 20 is determined by the heavy chain of the moisture separation reheater, but at least 2 for one bottom plate 21.
It is preferable to arrange them separately.

In the moisture separation reheater configured in this way, the rotary casters 20 are rotatable in all directions on the horizontal plane and around the vertical rod, so that the cross-around inlet pipe 3
Also, thermal displacement due to thermal expansion of the cross-around outlet pipe 5 can be sufficiently absorbed. As a result, the moisture separation reheater can be maintained and the health of the plant can be ensured without generating a large amount of stress on the cross-around inlet pipe 3, the cross-around outlet pipe 5, and the main body shell 4.

FIG. 2 shows another embodiment of the present invention, in which a rotary leg wheel 20 is disposed on the side surface of the support leg 17 with a support member 23 interposed therebetween. Even in such a moisture separator reheater, the same effects as the moisture separator reheater shown in FIG. 1 can be obtained.

FIG. 3 shows still another embodiment of the present invention, in which support legs 17 are arranged on both sides and the center of the main body trunk 4, and rotary leg wheels 20 are arranged on each support m17. has been done. Even in this embodiment, the same effect as the moisture separation reheater shown in FIG. 1 can be obtained. This embodiment is particularly applicable when the moisture separator reheater is heavy.

FIG. 4 shows still another embodiment of the present invention, in which support legs 17 are arranged on both sides and the center of the main body trunk 4, and rotary legs 20 are arranged only on the supports 1917 on both sides. ing. In addition, the bottom plate 2 of the support leg 17 arranged in the center
1 does not use foundation bolts.

In the moisture separator reheater configured in this way, since the support leg 17 disposed in the center is not fixed with the foundation bolts, the bottom surface of the bottom plate 21 acts as a sliding surface, and the moisture separation shown in FIG. Cross-around inlet pipe 3 as well as separator reheater
Also, thermal displacement due to expansion of the cross-around outlet pipe 5 can be absorbed.

FIG. 5 shows still another embodiment of the present invention, in which a pair of rolling mechanisms 24 are arranged on both sides of the support leg 17.

As shown in FIGS. 6, 7, and 8, this rolling mechanism 24 is constructed by housing a large number of steel balls 27 in a box 26 partitioned by a partition plate 25. The diameter of the steel ball 27 is slightly larger than the height of the box 26, and the diameter of the steel ball 27 is slightly larger than the height of the box 26.
5 is formed with a steel ball fall prevention claw 28 that prevents the steel ball 27 from falling out of the box 26.

In the moisture separator reheater constructed as described above, the steel balls 27 perform the same function as the rotary casters 20, so the moisture separator reheater constructed as described above has the same function as the moisture separator reheater shown in FIG. effect can be obtained.

[Effects of the Invention] As described above, in the moisture separator reheater of the present invention, the supporting legs are placed on the floor via a rolling mechanism, so that the cross-around inlet pipe and the cross-around outlet pipe are Displacement due to thermal expansion can be reliably absorbed by the movement of the main body shell, and a large amount of thermal stress occurring in the cross-around inlet pipe, cross-around outlet pipe, and main body shell can be effectively prevented.

[Brief explanation of the drawing]

Figures 1 to 5 are side views showing embodiments of the moisture separation reheater of the present invention, Figure 6 is an external view showing the rolling mechanism of Figure 5, and Figure 7 is a cross-sectional view of Figure 6. Front view, Figure 8 is the 6th
Figure 9 is a main steam pipe system diagram of the turbine and moisture separation reheater loli of a reheating nuclear power plant.
Fig. 0 is an explanatory diagram showing thermal deformation of the moisture separator reheater shown in Fig. 1, Fig. 11 is an explanatory diagram showing an example of the thermal deformation analysis results of the moisture separator reheater, and Fig. 12 is an explanatory diagram showing the thermal deformation of the moisture separator reheater shown in Fig. 1. 13 is a side view showing an enlarged view of the support leg on the right side of FIG. 12; FIG. 14 is a bottom view of FIG. 13; FIG.
The figure is an enlarged side view of the left support leg in FIG. 12, and FIG. 16 is a bottom view of FIG. 15. 2... High pressure turbine 3...
・・・・・・Cross-around inlet pipe 4・・・・・・
......Main body shell 5...Cross-around-outlet pipe 6...Low pressure turbine 17...
・・・・・・・・・Support leg 20・・・・・・・・・Rotating leg wheel Representative Patent attorney Noriyuki Noriyuki (and 1 other person) Figure 1 Figure 2 Figure 3 Figure 3 Straw Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 10 Figure 13 Figure 14 Figure 15 Figure 16

Claims (3)

[Claims] (1) A moisture absorber in which a cross-around inlet pipe connected to a high-pressure turbine and a cross-around outlet pipe connected to a low-pressure turbine are directly connected to the main body shell, and the main body shell is supported on the floor by a plurality of support legs. A moisture separation reheater, characterized in that the support legs are placed on a floor via a rolling mechanism. (2) The moisture separator reheater according to claim 1, wherein the rolling mechanism comprises rotary casters. (3) The moisture separator reheater according to claim 1, wherein the rolling mechanism comprises a plurality of steel balls housed in a box.