JPH0835601A - Sludge-collecting device in vertical steam generator - Google Patents

Abstract

PURPOSE:To achieve an invariably stabilized high efficiency in collecting the sludge in a vertical steam generator. CONSTITUTION:A sludge-collecting device 30 is provided in a vertical steam generator 20 which has a plurality of swirl type steam separators 23 placed above a region of feedwater boiling under heat and has also a moisture separator placed above the steam separators. Between steam separators 23 a sludge- collecting box 31 with an inflow port 33 in the middle of the upper side and an outflow port 35 in the upper side at the periphery is provided. With a directly-impinging-flow arrester 37 directly above, the inflow port receives the separated water from the moisture separator. In addition, the separated water B from the steam separators 23 falls on the upper side of the sludge-collecting box 31 and is in part taken into a perforated cylinder 39 of the directly- impinging-flow arrester.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a rigid steam generator used in a pressurized water reactor plant or the like, and more particularly to a sludge recovery device provided above the inside thereof.

[0002]

2. Description of the Related Art In a rigid steam generator, a high-temperature fluid flows through a heat transfer tube provided at a lower portion of the steam generator to heat and feed water to the outside. 2 of steam and water made in this way
The phase flow flows into the upper swirl vane type water-water separator, centrifugal force separates steam and water, and the separated water falls and is returned to the heating region.

Since the steam exiting the steam separator still contains fine water droplets, it passes through a zigzag passage type moisture separator provided further above, where the water droplets are separated.
These separated water droplets also collect and become separated water, which is returned to the lower heating region.

In such a rigid steam generator, in order to prevent sludge from accumulating in the steam generator,
Sludge recovery equipment is provided. An example thereof will be described with reference to FIGS. 2 and 3. The upper body 1 of the steam generator 10
Three swirl vane type water-water separators 13 are provided in one. In this type of steam-water separator 13, the two-phase flow that has risen in the inner cylinder 13a is given a centrifugal force by the swirl vanes 13b, and the separated water flows between the outer cylinder 13c and the inner cylinder 13a.
Run down. The sludge recovery device 15 is provided in the lower part between the steam separators 13, and has an inlet port 15a on the upper surface of the central part thereof.
An outlet 15b is formed on the upper surface of the outer peripheral portion. This sludge recovery device 15 is used for the water supply ring header 1 during normal operation.
It is below the liquid surface 19a of the water supply 19 supplied from 7.

Then, a part of the secondary separated water a, which drops from a moisture separator (not shown) located further above through the central pipe 18, flows into the sludge recovery device 13 from the inflow port 15a and flows. It flows out from the outlet 15b. During this time, the wake sludge is separated by sedimentation and collected in the sludge recovery device 15. On the other hand, the separated water from the steam separator 13, that is, the primary separated water b, flows down toward the upper surface of the sludge recovery device 15, and then flows toward the upper cylinder 11 along the sludge recovery device 15, and the running water ring header 17 It joins with the water supply from and flows toward the heating part below. The secondary separated water a that did not flow into the sludge recovery device 15 also flows along the upper surface thereof.

[0006]

In the conventional sludge recovery device described above, the secondary separated water that falls by gravity is directly exposed to the inflow port, and a part of it is guided to the inside of the device to pass therethrough to collect the sludge. However, the flow rate of the secondary separated water greatly increases or decreases depending on the operating conditions of the steam generator.

On the other hand, according to the knowledge of the inventor, the sludge settling separation characteristic in the recovery device largely depends on the flow velocity of water passing therethrough, and if it deviates from an appropriate flow velocity value, the performance is greatly reduced. However, since the flow rate of the secondary separated water in the steam generator is likely to change greatly, it was not always possible to obtain sufficient sludge recovery performance.

[0008] Therefore, the present invention has been made for the purpose of providing a sludge recovery device which can always obtain a high recovery performance in a rigid steam generator.

[0009]

For the purposes of the above, according to the invention, a plurality of swirl-type steam-water separators provided above the heating and boiling area of the feed water and above the steam-water separators are provided. The sludge recovery device provided in the rigid steam generator having the moisture separator provided in is configured as follows. That is, the sludge collection box is provided between the steam separators, and the inlet is provided on the upper surface of the central portion and the outlet is provided on the upper surface of the outer peripheral portion. Then, a direct flow preventer is installed directly above the inflow port, is configured to receive the separated water from the moisture separator, and the separated water from the steam separator is on the upper surface of the sludge collection box. If it falls, the perforated cylinder of the direct flow preventer
It is configured to accept a portion of its separated water.

[0010]

In the above structure, the separated water (primary) dropped from the steam separator is divided into an outer peripheral direction flow and a central direction flow on the upper surface of the sludge collection box and flows horizontally. The central flow hits the perforated cylinder of the direct flow preventer and is stopped,
Increase head. On the other hand, the flow in the outer peripheral direction flows over the outlet,
The pressure inside the collection box is reduced only by the dynamic pressure. That is, in the collection box, a pressure difference occurs between the vicinity of the inlet and the vicinity of the outlet,
This causes a flow from the inlet to the outlet. In other words, a part of the central flow generated by falling from the steam separator enters the sludge collection box through the inflow port and flows there, dropping sludge. Then, it flows out from the outlet and recirculates to the heating / boiling region.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, the upper body 2 of the steam generator 20
In 1, the swirl type water-water separator 23 has three equal circumferential intervals.
It is provided individually. Of course, the steam separator 23 may be two in number depending on the size of the steam generator 20, or may be an appropriate number of four or more. Such a steam separator 2
The arrangement of 3 is the same as that of the above-mentioned conventional structure, and FIG.
See for a better understanding. As can be easily imagined from this, a moisture separator (secondary separator) (not shown) is provided above the steam separator 23, and the separated water (secondary separated water) from this moisture separator is provided. A central tube 28 through which a) flows.

In the steam generator 20 having such a structure, the low temperature feed water 29 flowing in from the feed water ring header 27.
Flows down along the inner surface of the upper cylinder 21, further flows down along the inner surface of the lower cylinder (not shown), and enters the heating / boiling region.
While rising in the heating boiling region, it is heated and boils into a two-phase flow of steam and water.

The two-phase flow of steam and water is the steam separator 23.
It rises in the inner cylinder 23a and becomes a swirl flow by the swirl vanes 23b. The water is pressed against the inner surface of the inner cylinder 23a by centrifugal force to become separated water, and the inner cylinder 23a and the outer cylinder 23c are separated.
It enters the annular flow path between and flows down. Arrow B indicates the flow of such separated water (primary separated water). On the other hand, the steam with a small specific weight is used for the upper opening 23d of the steam separator 23d.
Through the moisture separator (not shown) to be separated into dry steam and water droplets. The separated water drops and the like become (secondary) separated water A and flow down in the central pipe 28.

The sludge recovery device 30 for recovering sludge from the primary separated water B and the secondary separated water A is constructed as follows. That is, the collection box body 31 having an outer shape similar to that of the conventional one described above is provided between the inner cylinders 23 a of the steam separator 23. Then, on its upper surface, an inflow port 33 having a relatively large diameter is bored in the central portion,
In addition, a plurality of outlets 35 having a relatively small diameter are formed in the outer peripheral portion. Since the planar shape of the collection box 31 is the same as the conventional one described above, the outflow ports 35 are provided at the three outer peripheral ends, respectively.

Further, above the inflow port 33 of the collection box 31,
A direct flow preventer 37 is provided. Direct flow preventer 37
Is generally cylindrical, has a perforated cylinder 39 in the lower part, and has a direct flow prevention plate 41 above it.

The sludge recovery device 30 having the above structure
The secondary separated water A flowing down in the central pipe 28 hits the direct flow prevention plate 41, overflows to the outside of the direct flow prevention device 37, and falls around the perforated cylinder 39. Further, the primary separated water B dropped from the steam separator 23
A part of the heading toward the center and approaching the perforated cylinder 39,
It merges with the above-mentioned secondary separated water A to increase the head of this portion.
On the other hand, the rest of the primary separated water B flows in the outer peripheral direction on the upper surface of the sludge collection box 31, flows over the outflow port 35, and causes a suction action. In this way, the sludge collection box 3
A flow C flowing from the inflow port 33 to the outflow port 35 is generated in the No. 1, and since the flow velocity is small, the sludge that was accompanying the flow settles, is separated, and is collected.

[0017]

As described above, according to the present invention, the secondary separated water from the moisture separator is received by the direct flow preventer, and the secondary separated water is discharged from the steam separator onto the sludge collection box. The flow of the primary separation water that falls and the perforated cylinder of the direct flow preventer cooperate to generate a flow through the sludge collection box.
Sludge is collected. Since the flow rate of the primary separated water from this steam separator is stable during the operation of the steam generator, the flow through the sludge collection box is also stable and sludge recovery is always performed with high efficiency. be able to.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a plan sectional view of a conventional device.

FIG. 3 is a vertical cross-sectional view of a conventional device.

[Explanation of symbols]

20 ... Steam generator, 23 ... Steam separator, 30 ... Sludge recovery device, 31 ... Sludge collection box, 33 ... Inflow port, 35
... Outlet port, 37 ... Direct flow preventer, 39 ... Perforated cylinder, 41
... direct flow prevention plate, A ... secondary separated water, B ... primary separated water.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takaya Kusakabe 1-1-1 Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Heavy Industries Ltd. Kobe Shipyard

Claims (1)

[Claims] 1. A rigid steam generator having a plurality of swirl type steam-water separators provided above a heating and boiling region of feed water and a moisture separator provided above the steam-water separators. A sludge collection box having an inflow port and an outflow port separated from each other is provided so as to be sandwiched by the steam separator, and the separated water of the steam separator falls on the upper surface of the sludge collection box. And a direct flow preventer having a perforated cylinder is provided directly above the inflow port so that the separated water from the moisture separator falls on the direct flow preventer. A sludge recovery device for a rigid steam generator, which is characterized in that