JPH0563682B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a separator for removing moisture from steam, and in particular to a moisture separator or a moisture separator reheater applied to nuclear power plants, etc. Regarding structure.

[Background of the invention]

In nuclear power plants, turbines. The steam used to drive the generator is close to saturation. Therefore, if the steam is thermally expanded in the high-pressure turbine and then thermally expanded in the low-pressure turbine, the moisture content in the steam will be around 20% to 25%, which will cause erosion of the turbine blades and reduce turbine efficiency. Therefore, it is necessary to perform some kind of treatment on the steam exiting the high-pressure turbine. Treatment of this steam may include removing moisture from the steam and possibly reheating the dried steam to a temperature close to the steam temperature entering the high-pressure turbine.
This function is accomplished by a moisture separator or moisture separator reheater.

A moisture separator or moisture separator reheater has separation devices arranged longitudinally inside a horizontally long pressure vessel.
A reheating device is arranged above it. The steam that enters through at least one inlet opening at the bottom of the container is split in the longitudinal direction and passed through a separator to mechanically remove moisture in the steam, and then to at least one inlet opening at the top. It flows out from the outlet opening, or flows out from the outlet opening after passing through the reheating device.

The flow path formed in the pressure vessel from the inlet opening to the separator has a generally rectangular shape and a semicircular shape at the bottom, so as to divert most of the steam longitudinally at the inlet opening. Since the shaped flow path is formed in the longitudinal direction, each vapor follows a longitudinal trajectory along the semicircular shape to the upper separation device. With this channel shape, the water in the steam will follow different trajectories due to the difference in inertia between the steam and water due to the flow turning, and as the water adheres to the inner wall of the container, it will flow backwards to the bottom. In order to suppress as much as possible the accompanying steam that accompanies drain discharge, it is necessary to use gravity flow, in which case a water level is formed at the bottom, and the separated drain There was a drawback that the separation effect was lowered because the main stream of steam was entrained again by the mainstream steam flow. In addition, during a transient stage such as when a plant is started up, the amount of condensate generated increases further due to the condensation of steam caused by the temperature difference between the steam and metal inside the pressure vessel, etc., and the condensate generated inside the vessel is entrained. The problem was that the moisture in the steam increased, especially in low-load areas where temperature changes were large.

[Purpose of the invention]

An object of the present invention is to provide a moisture separator that can enhance the moisture separation effect within the moisture separator and suppress the introduction of excessive moisture-containing steam during startup.

[Summary of the invention]

That is, the present invention provides a semicircular container which is disposed at the bottom of a cylindrical container away from the inlet opening, spaced apart from the wall surface of the bottom, has a large number of holes, and is closed on the inlet opening side. In order to achieve the intended purpose, a guide plate is provided and at least one drain hole is provided at the bottom of the cylindrical container facing the guide plate.

[Embodiments of the invention]

An embodiment of the present invention will be described below.

FIG. 1 shows an equipment system diagram of a steam turbine facility in a nuclear power plant equipped with a moisture separator. In FIG. 1, steam generated in a nuclear reactor or steam generator 1 flows into a high-pressure turbine 3 via a main steam pipe 2 and is converted into rotational energy by thermal expansion. Since high-pressure turbine exhaust normally contains 10% to 12% moisture, the moisture separator 5 installed in the middle of the cross-around pipe 4
Most of the moisture in the steam is separated and is reduced to 0% to 2%.
% wet steam flowing into the lowering turbine 6,
After repeating thermal expansion again, it is converted into rotational energy, which rotates the generator 7 to generate electricity. On the other hand, the low-pressure turbine exhaust gas is condensed in the condenser 8 to become condensate, and is recovered to the nuclear reactor or steam generator 1 via the feed water heater 9, feed water pump 10, etc.
The heat of the drain separated therein is recovered to the feed water heater 9 via the drain tank 11. FIG. 2 is a cross-sectional view of the moisture separator 5. In FIG. 2, the moisture separator 5 has an inlet opening 13 at the bottom of an oblong cylindrical pressure vessel 12 and an outlet opening 14 at the top, and is used to remove moisture after leaving the high-pressure turbine 3. The dried steam flows in through the inlet opening 13, and the dried steam flows out through the outlet opening 14 and flows into the low pressure turbine 6. Inside the pressure vessel 12, a pair of V-shaped separation devices, ie, separation element bundles 15, are arranged longitudinally along the axis of the vessel and approximately symmetrically about the axis. As a result, an inlet steam chamber 16 and an outlet steam chamber 17 are formed. Longitudinal plates 18 are mounted and supported on both sides of the separation element bundle 15 so that all of the moist steam passes through the separation element bundle 15. The separation element bundle 15 is formed of a plurality of corrugated plates spaced apart at regular intervals to form a zigzag-shaped flow path. Water droplets separated from the steam by inertial force flow down along the corrugated plate, and a partition plate 19 extending longitudinally along the bottom line of the V-shaped separation element bundle 15 and a semicircular bottom part 20 are formed.
After being discharged into the channel (tray) formed by
The heat is collected, discharged from the drain discharge hole 21, and recovered by the system. In order to make the moisture separator 5 work more efficiently, it is necessary to provide a uniform flow velocity distribution within the separation element bundle 15 consisting of zigzag channels. Therefore, in the inlet steam chamber 16 that forms a flow path in the longitudinal direction from the inlet opening 13, the steam flow rate is high immediately after the inlet opening 13, but is gradually distributed and decelerated. Since the flow rate is almost uniform at the inlet, the flow velocity is close to uniform when flowing upward along the semicircular flow path. Therefore,
Due to the difference in inertial force within the semicircular internal flow path, water droplets adhering to the inner wall of the pressure vessel 12 become uniform in the longitudinal direction, and as shown in the internal structure diagram of the inlet steam chamber shown in FIG. By separating the guide plate 24 from the inner surface of the semicircular portion at the bottom of the pressure vessel 12 and attaching it with the mounting member 25, the drain separated above the guide plate 24 is connected to the inner surface of the pressure vessel 12 through the hole 23. It flows down the flow path 26 formed between the lower surfaces of the guide plates 24 and is discharged from the drain discharge hole 27 provided at the bottom of the pressure vessel 12, and is not accompanied by the mainstream steam flow. The drain that is separated further above the guide plate 24, adheres to the inner surface of the pressure vessel 12, and flows down flows down a flow path formed from the inner surface plate 24 of the pressure vessel 12. On the other hand, by providing the guide plate 24, the flow path in the inlet steam chamber 16 is narrowed, and the influence on the flow velocity distribution at the inlet of the separation element bundle 15 is minimized. The width of the flow path formed by the guide plate 24 can be made non-uniform in the circumferential direction, such as the X dimension at the bottom and the Y dimension at the upper end of the guide plate 24, to ensure a main stream steam flow path. In addition, since the steam flow velocity is high on the inlet opening 13 side, the longitudinal end face of the guide plate 24 is sloped in the longitudinal direction of the guide plate 24 to stabilize the flow velocity and to direct the separated drain to the inlet opening 13. Backflow can be prevented.

〔Effect of the invention〕

According to the present invention, it is possible to enhance the moisture separation effect and suppress the introduction of excessive moisture-containing steam during startup and the like.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a turbine equipment equipped with a moisture separator in a nuclear power plant, and FIGS. 2 a, b, and c are cross-sectional views of the overall structure of a moisture separator according to an embodiment of the present invention. FIGS. 3a, 3b and 3c are sectional views showing the structure of an embodiment of the present invention. 5... Moisture separator, 12... Cylindrical container, 13
...Inlet opening, 14...Outlet opening, 15...
Separation element bundle, 16...Inlet steam chamber, 17...
...Exit steam chamber, 24...Guide plate, 26...Drain channel, 27...Drain discharge hole.

Claims (1)

[Scope of Claims] 1. A cylindrical container having at least one inlet opening at the bottom through which wet steam flows in and at least one outlet opening at the top through which dry steam exits; and this cylindrical container. A moisture separator comprising: a pair of separators arranged along the longitudinal direction of the interior to remove moisture from the inflowing wet steam; and a tray and a drain discharge hole for discharging the drain separated by the separators. In the apparatus, at the bottom of the cylindrical container avoiding the inlet opening,
A semicircular guide plate is provided that is spaced apart from the wall surface of the bottom, has a large number of holes, and is closed on the inlet opening side, and a cylindrical container facing the guide plate is provided. A moisture separator, characterized in that the bottom part is provided with at least one drain hole. 2. Claim 1, characterized in that the distance between the guide plate and the bottom of the cylindrical container gradually decreases toward the circumferential end of the guide plate. moisture separator. 3. The moisture absorbent according to claim 2, characterized in that the guide plate extending in the longitudinal direction of the bottom of the cylindrical container gradually expands in the radial direction near the inlet opening. Separation device.