JPH0463109A - Cross-around pipe provided with moisture separator - 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 [Object of the Invention] (Industrial Application Field) The present invention relates to a cross-around pipe with a moisture separator used in a steam turbine of a nuclear power plant.

(Prior art) The exhaust steam of a high-pressure steam turbine in a nuclear power plant is about 12% wet steam, and in order to remove this moisture, multiple large moisture separators are generally installed in the middle of the cross-around pipe. installed to supply steam from which moisture has been removed to a low-pressure steam turbine.

This moisture separator has a corrugated moisture separation element installed inside the pressure vessel, which separates and captures the moisture in the steam, guides it to a drain tank, and guides it to a feed water heater etc. while controlling the water level to heat it. It is common to try to recover the waste.

A nuclear power plant equipped with this moisture separator is composed of equipment as shown in FIG. Namely.

The steam that has completed its work in the high pressure steam turbine 1 passes through a cross-around pipe 2 into a moisture separator where the moisture is removed. This steam is sent to a low pressure steam turbine 4 via a cross-around pipe 2. The moisture separator 3 is provided with a drain tank 6, and the drain separated within the vessel is collected there.This drain passes through a drain pipe 7 and a water level control valve 8, and is collected in the feed water heater 9, and is then collected in the feed water heater 9. is heated. In addition, the code|symbol 5 has shown the air bleed pipe.

(Problems to be Solved by the Invention) In the conventional technology, all the moisture contained in the exhaust steam of a high-pressure steam turbine is separated by passing it through a moisture separator, so the moisture separator itself becomes large. This tendency is becoming stronger as plant output increases, and it has become a major bottleneck in plant layout. Furthermore, the drain tank of the moisture separator and its water level control device are also becoming larger.

Therefore, one purpose of the present invention is to separate and extract a certain amount of moisture contained in exhaust steam in advance in the path from the high-pressure steam turbine to the moisture separator, thereby reducing the moisture in the steam flowing to the moisture separator. It is an object of the present invention to provide a cross-around tube with a moisture separator that allows the moisture separator to hold the moisture separator.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a cross-around pipe that connects a high-pressure turbine and a low-pressure turbine, in which steam is approximately Vertical force number 16! In the case where the elbow part is configured so that the flow changes direction in the horizontal direction, the bleed pipe is connected directly below the elbow part, facing vertically, and keeping the same 1.11 angle as the cross-around pipe. , the air bleed pipe has an air bleed pipe take-out part that has an inner diameter that is almost the same as the inner diameter of the cross-around pipe, and an air bleed pipe that has an inner diameter that is smaller than or equal to the inner diameter of the cross-around pipe.
It is characterized in that it is equipped with an air bleed pipe section having an inner diameter of J%, and the outlet of the air bleed pipe section is connected to a feed water heater.

(Function) In the two-phase flow of steam and condensate containing about 12% humidity in the cross-around pipe, the direction of the steam flow is
If the drain is forcibly changed by a cross-around pipe), the drain will be shifted to one side. Therefore, when the cross-around pipe is laterally turned directly downward as in the present invention, the drain has an inertia force in the downward direction. Therefore, if a part is provided to capture the condensate in this part, the condensate will be pressed against this part by the action of inertia and gravity. In the present invention, a bleed pipe is provided in the portion where this drain is captured, and the captured drain along with the bleed steam is guided to the feed water heater.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1, 2, and 3.

Steam turbine equipment for a nuclear power plant generally includes a high-pressure steam turbine 1 and a low-pressure steam turbine 4, and exhaust steam from the high-pressure steam turbine 1 is guided to the low-pressure steam turbine 2 through a cross-around pipe 2.

Generally, a moisture separator 3 is provided in the middle of the cross-around pipe 2 to remove moisture contained in the exhaust steam. Here, the steam flow path is indicated by arrow A. The steam expanded by the high-pressure steam turbine 1 is wet steam containing about 12% humidity. When this steam is led to the cross-around pipe 2, it flows vertically directly downward (indicated by a dashed line B in the figure), but a bleed pipe 5 is installed at the bottom in the same direction. The E section of the bleed pipe 5 has the same inner diameter as the cross-around pipe. This is used as the air bleed pipe 5, and the size is further reduced by the F section to the required diameter. In such a configuration, the steam within the cross-around tube 2 can relatively easily change its direction from the vertical direction B to the horizontal direction C, as shown by the dotted arrow A'. On the other hand, the moisture contained in the steam flows relatively easily along the inner wall of the cross-around pipe 2. This flow is shown by a dashed line G. If configured in this way, it becomes possible to separate about 30 to 40% of the moisture flowing through the cross-around pipe 2 according to the extracted steam. Therefore, the humidity of the steam flowing in the cross-around pipe 2 after this device can be reduced to about 7%.

〔Effect of the invention〕

As explained above, the present invention can improve the steam humidity in the cross-around pipe, which was conventionally about 12%, to about 7% by providing a moisture separator in the cross-around pipe. This results in 40% less condensate being separated in the downstream moisture separator, which reduces the moisture separator, moisture separator drain tank, moisture separator drain system and moisture separator. It becomes possible to reduce the capacity of the drain water level control valve by about 40%.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a cross-around tube with a moisture separator according to the present invention, FIG. 2 is an enlarged vertical sectional view of the moisture separator section shown in FIG. 1, and FIG. It is a schematic system diagram showing an example of a nuclear power plant. 1...High pressure turbine 2...Cross-around pipe 3...Moisture separator 4...Low pressure steam turbine 5
...Bleed Pipe Agent Patent Attorney Noriyuki Chika

Claims (1)

[Claims] A cross-around pipe that connects a high-pressure turbine and a low-pressure turbine, and has an elbow portion so that steam changes its flow direction from a substantially vertical direction to a substantially horizontal direction inside the vertically arranged cross-around pipe. In the configuration, an air bleed pipe is connected directly below the elbow portion facing vertically and concentrically with the cross-around pipe,
The air bleed pipe includes an air bleed pipe take-out part having an inner diameter that is approximately the same as the inner diameter of the cross-around pipe, and an air bleed pipe part that has an inner diameter smaller than the inner diameter of the cross-around pipe, and the outlet of the air bleed pipe part is connected to the water supply. A cross-around pipe with a moisture separator, characterized in that it is connected to a heater.