JP7087868B2 - Drain recovery tank for degassed water - Google Patents

Description

The present invention relates to a drain recovery tank for degassed water.

Conventionally, in a steam generator that generates steam by heating water supply, degassing treatment that removes dissolved oxygen contained in the water supply in order to suppress corrosion due to oxidation inside the can body that constitutes the steam generator. May be done. In such a steam generator, the degassed water supply (degassed water) is stored in a water supply tank, and water is supplied from the water supply tank to the can body.
In addition, in order to improve the heat utilization efficiency of the steam generator, the drain generated from the steam generated by the steam generator and used in the load equipment and the steam (flash steam) generated from this drain are stored in the water supply tank. A technique has also been proposed in which the degassed water is condensed, collected in a water supply tank, and reused (see, for example, Patent Document 1).

Here, in a steam generator that uses degassed water as water supply, if air is mixed inside the water supply tank when condensing the flash steam, the amount of dissolved oxygen in the degassed water increases. Therefore, in the technique proposed in Patent Document 1, the flash steam is condensed by the flash steam recovery box provided above the water supply tank, and then the drain is introduced into the water supply tank by the drain introduction pipe to generate the flash steam. It reduces the suction of air into the water supply tank when it is condensed.

JP-A-2017-0322222

However, in the technique proposed in Patent Document 1, it is necessary to provide a flash steam recovery box above the drain introduction pipe, which increases the size of the apparatus.

Therefore, an object of the present invention is to provide a drain recovery tank for degassed water that can be miniaturized.

In the present invention, heat is exchanged between the tank body for storing degassed water and the degassed water and the drain, and a mixture formed from a double pipe of an inner pipe for drain introduction and an outer pipe for flush steam recovery. A drain recovery tank for degassed water provided with an apparatus, wherein the upper end portion of the drain introduction inner pipe is arranged outside the tank body, and the lower end portion is arranged in the steam phase portion inside the tank body. The upper end of the flash steam recovery outer pipe is arranged outside the tank body, the lower end is arranged at the liquid phase part inside the tank body, and the drain introduction inner pipe and the drain introduction pipe are arranged outside the tank body. The present invention relates to a drain recovery tank for degassed water provided with a circulation line for circulating degassed water of the tank body between the outer pipes for flash steam recovery.

Further, it is preferable to further include a degassed water diffusion plate arranged between the drain introduction inner pipe and the flash steam recovery outer pipe.

Further, it is preferable to further include a flash steam exhaust unit arranged between the degassed water diffusion plate and the tank body.

According to the drain recovery tank for degassed water of the present invention, miniaturization can be realized.

It is a figure which shows the structure of the boiler system provided with the drain recovery tank for degassed water of this invention.

Hereinafter, a preferred embodiment of the drain recovery tank for degassed water of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a boiler system 100 including a drain recovery tank 1 for degassed water of the present embodiment.
In the present specification, the "drain recovery tank for degassed water" refers to a container (tank) for accommodating degassed water at room temperature introduced from an oxygen scavenger and high-temperature drain water returned by drain recovery.

The boiler system 100 of the present embodiment includes a boiler 110 as a steam generator, a load device 120, and a drain recovery tank 1 for degassed water. Further, the boiler system 100 connects these devices and has a steam supply line L1, a drain introduction line L2, a degassed water supply line L3, and a degassed water introduction line L4 as lines through which steam or water flows. , Equipped with. "Line" is a general term for lines that allow fluid to flow, such as channels, paths, and pipelines.

The boiler 110 heats the water supply supplied to the inside with the combustion gas to generate steam. In the present embodiment, the boiler 110 is supplied with degassed water stored in the tank body 10 described later as water supply.
The load device 120 uses the steam generated by the boiler 110 as a heat source to exchange heat with the object to be heated.

As shown in FIG. 1, the drain recovery tank 1 for degassed water recovers the drain generated from the steam generated in the boiler 110 and used in the load device 120 and the steam (flash steam) generated from the drain, and again. Supply to the boiler 110. The details of the drain recovery tank 1 for degassed water will be described later.

The steam supply line L1 connects the boiler 110 and the load device 120, and supplies the steam generated by the boiler 110 to the load device 120.
The drain introduction line L2 connects the load device 120 and the drain introduction inner pipe 21 constituting the drain recovery tank 1 for degassed water, and degass the drain and flash steam generated by using steam in the load device 120. It is introduced into the drain introduction inner pipe 21 constituting the water drain recovery tank 1. A steam trap 90 is arranged on the drain introduction line L2.

The degassed water supply line L3 connects the tank main body 10 constituting the degassed water drain recovery tank 1 and the boiler 110, and supplies the degassed water stored in the tank main body 10 to the boiler 110. A water supply pump 91 is arranged in the degassed water supply line L3.
The degassed water introduction line L4 connects a supply source of make-up water (not shown) and a tank body 10 constituting the drain recovery tank 1 for degassed water. A make-up water pump 92 and an oxygen scavenger 93 are arranged in the degassed water introduction line L4 from the upstream side to the downstream side. The degassed water introduction line L4 introduces the make-up water degassed by the deoxidizing device 93, that is, the degassed water into the tank body 10.

The drain recovery tank 1 for degassed water includes a tank main body 10, a mixing device 20, a flush steam exhaust unit 30, a circulation line L5, a circulating water accommodating unit 40, and a degassed water diffusion plate 50.

The tank body 10 stores degassed water. An inspection opening 11 and an overflow port 12 are provided in the upper part of the tank body 10.

The inspection opening 11 is arranged on the upper surface of the tank body 10. The inspection opening 11 includes an inspection opening and a lid member that can be detachably attached to the inspection opening.
The overflow port 12 is arranged on the side surface of the tank body 10. The overflow port 12 discharges the degassed water in the tank body 10 from the inside to the outside when the water level in the tank body 10 rises.
The tank body 10 contains granular suspended matter such as beads covering the water surface of the stored degassed water, and these granular suspended matter are suspended on the water surface of the degassed water, so that the air in the gas phase portion is contained. Is suppressed from re-dissolving.

The mixing device 20 is formed of a double pipe of a drain introduction inner pipe 21 and a flash steam recovery outer pipe 22, and exchanges heat between the degassed water and the drain.

The drain introduction inner pipe 21 is arranged in the gas phase portion A inside the tank body 10 so that the upper end portion is connected to the drain introduction line L2 outside the tank body 10 and the lower end portion opens downward. The drain introduction inner pipe 21 introduces drain and flush steam from the lower end into the inside of the tank body 10. In the present embodiment, the lower end of the drain introduction inner pipe 21 is located above the overflow port 12.

The flash steam recovery outer pipe 22 extends in the vertical direction so as to surround the drain introduction inner pipe 21. The flash steam recovery outer pipe 22 includes a lower outer pipe portion 221, a central outer pipe portion 222 that constitutes the flash steam exhaust portion 30, and an upper outer pipe portion 223 that constitutes the circulating water accommodating portion 40.
The flash steam recovery outer pipe 22 recovers the flash steam by condensing the flash steam introduced through the drain introduction inner pipe 21.
The upper end of the lower outer pipe portion 221 is connected to the flash steam exhaust portion 30 (central outer pipe portion 222) outside the tank body 10, and the lower end portion extends to the liquid phase portion W inside the tank body 10.

The flash steam exhaust portion 30 includes a central outer pipe portion 222 configured in a tubular shape having substantially the same diameter as the lower outer pipe portion 221. The lower end of the flash steam exhaust portion 30 (central outer pipe portion 222) is connected to the upper end portion of the lower outer pipe portion 221. An opening that is open to the outside is formed on the side surface of the flash steam exhaust unit 30. A flush vapor relief line (not shown) is connected to this opening, and a flush vapor relief valve (not shown) is arranged in the flash vapor relief line. By opening the flash steam relief valve, the flash steam exhaust unit 30 discharges the flash steam that has not been condensed by the mixing device 20 to the outside via the flash steam relief line.

The circulating water accommodating portion 40 includes a lower outer pipe portion 221 and an upper outer pipe portion 223 configured in a tubular shape having substantially the same diameter as the central outer pipe portion 222. The lower end of the circulating water accommodating portion 40 (upper outer pipe portion 223) is connected to the upper end portion of the flash steam exhaust portion 30 (central outer pipe portion 222) via the degassed water diffusion plate 50 described later. The upper end of the circulating water accommodating portion 40 (upper outer pipe portion 223) is closed except for the portion through which the drain introduction inner pipe 21 penetrates. A circulation line L5 is connected to the side surface of the circulating water accommodating portion 40. The circulating water accommodating portion 40 accommodates degassed water circulated from the tank body 10 by the circulation line L5.
The shape of each pipe such as the drain introduction inner pipe 21 and the flash steam recovery outer pipe 22 is not limited to a cylinder, and may be a square cylinder (for example, a square cylinder).

The circulation line L5 connects the tank main body 10 and the circulating water accommodating portion 40, and circulates the degassed water in the tank main body 10 between the drain introduction inner pipe 21 and the flash steam recovery outer pipe 22. A circulation pump 94 is arranged on the circulation line L5.
In the present embodiment, the operation of the circulation pump 94 is controlled based on the temperature of the degassed water stored inside the tank body 10. More specifically, when the temperature of the degassed water stored inside the tank body 10 is equal to or lower than a predetermined set temperature, the circulation pump 94 operates to circulate the degassed water. Further, when the temperature of the degassed water exceeds the set temperature, the operation of the circulation pump 94 is stopped, and the circulation of the degassed water is stopped.

The degassed water diffusion plate 50 is a plate-shaped member arranged between the upper end of the flush steam exhaust portion 30 and the lower end of the circulating water accommodating portion 40 so as to surround the drain introduction inner pipe 21, and has a large number of through holes. It is composed of the punching metal on which 51 is formed. The degassed water diffusion plate 50 supplies the degassed water contained in the circulating water accommodating unit 40 to the flash steam exhaust unit 30 in a state of being diffused through the through hole 51.

According to the above drain recovery tank 1 for degassed water, the drain and flash steam generated by using the steam generated in the boiler 110 in the load device 120 circulates in the drain introduction line L2 and is an inner pipe for drain introduction. Introduced in 21. The drain and flush steam introduced into the drain introduction inner pipe 21 are introduced into the gas phase portion A inside the flash steam recovery outer pipe 22 from the lower end of the drain introduction inner pipe 21.

The drain introduced into the gas phase portion A inside the flash steam recovery outer pipe 22 falls and is introduced into the liquid phase portion W in the tank body 10. The drain introduced into the liquid phase portion W exchanges heat with the degassed water in the liquid phase portion W.
On the other hand, in the flash steam introduced into the gas phase portion A inside the outer pipe 22 for collecting the flash steam, the degassed water circulated from the tank body 10 through the circulation line L5 and stored in the circulating water accommodating portion 40. It is supplied in a state of being diffused to the flash steam exhaust section 30 through a large number of through holes 51 of the degassed water diffusion plate 50. As a result, the degassed water supplied to the flash steam exhaust unit 30 exchanges heat with the flash steam flowing into the flash steam exhaust unit 30 to condense the flash steam. The degassed water supplied from the degassed water diffusion plate 50 and the condensed water in which the flash steam is condensed are recovered in the liquid phase portion W in the tank body 10 through the flash steam recovery outer pipe 22.
Further, the flash steam that has not been condensed by the degassed water supplied to the inside of the flash steam recovery outer pipe 22 is discharged to the outside from the flash steam exhaust unit 30. In the present embodiment, the flash steam is discharged from the flash steam exhaust unit 30 in a state where the degassed water is not circulated by the circulation line L5. That is, in a state where the degassed water is circulated by the circulation line L5, the flash steam relief valve is closed and the discharge of the flash steam from the flash steam exhaust unit 30 is stopped. Then, in a state where the circulation of the degassed water by the circulation line L5 is stopped, the flash steam relief valve is opened and the flash steam is discharged from the flash steam exhaust unit 30.

The degassed water in the tank body 10 flows through the degassed water supply line L3 and is supplied to the boiler 110. When the water level in the tank body 10 drops, the make-up water degassed by the oxygen scavenger 93 flows through the degassed water introduction line L4 and is introduced into the liquid phase portion W.

According to the drain recovery tank 1 for degassed water of the present embodiment described above, the following effects are obtained.

The drain recovery tank 1 for degassed water exchanges heat between the tank body 10 for storing the degassed water and the degassed water and the drain, and the drain introduction inner pipe 21 and the flash steam recovery outer pipe 22. A mixing device 20 formed of a double tube is provided. The upper end of the drain introduction inner pipe 21 is arranged outside the tank body 10, and the lower end thereof is arranged in the gas phase portion A inside the tank body 10. The upper end of the flash vapor recovery outer tube 22 is arranged outside the tank body 10, and the lower end thereof is arranged in the liquid phase portion W inside the tank body 10. The drain recovery tank 1 for degassed water includes a circulation line L5 that circulates the degassed water of the tank body 10 between the drain introduction inner pipe 21 and the flush steam recovery outer pipe 22 outside the tank main body 10.

Therefore, in the flash steam recovery outer pipe 22 arranged so as to surround the drain introduction inner pipe 21, the flash steam is condensed into degassed water, so that a device for recovering the flash steam is separately provided. It is not necessary to provide it, and space saving of the mixing device 20 can be realized. As a result, the size of the drain recovery tank 1 for degassed water can be reduced. Further, the lower end of the drain introduction inner pipe 21 is arranged in the gas phase portion A and does not reach the liquid phase portion W. As a result, since the flash vapor is not directly introduced into the liquid phase portion W, it is possible to suppress the generation of water hammer (vibration) caused by the condensation of the flash vapor in the liquid phase portion W.
Further, since the lower end portion of the flash steam recovery outer pipe 22 is positioned at the liquid phase portion W, this fluctuation also occurs when the water surface of the liquid phase portion W fluctuates inside the flash steam recovery outer pipe 22. It can be prevented from being transmitted to the water surface of the liquid phase portion W on the outside of the flash steam recovery outer pipe 22. Therefore, it is possible to prevent an increase in contact between the degassed water and the air due to the fluctuation of the water surface of the liquid phase portion W, and thus it is possible to suppress an increase in the amount of dissolved oxygen in the degassed water.

Further, the degassed water drain recovery tank 1 further includes a degassed water diffusion plate 50 arranged between the drain introduction inner pipe 21 and the flash steam recovery outer pipe 22. As a result, the degassed water can be brought into contact with the flash steam introduced into the gas phase portion A inside the outer tube 22 for collecting the flash steam in a state where the degassed water is diffused by the degassed water diffusion plate 50. Therefore, since the degassed water and the flash steam can be effectively brought into contact with each other with a simple configuration, the drain recovery tank 1 for degassed water can be further miniaturized.

Further, the drain recovery tank 1 for degassed water further includes a flush steam exhaust unit 30 arranged between the degassed water diffusion plate 50 and the tank main body 10. As a result, the flash steam that has not been condensed by supplying the degassed water can be discharged to the outside from the degassed water drain recovery tank 1, so that the safety of the degassed water drain recovery tank 1 can be improved. ..

Although the preferred embodiment of the drain recovery tank 1 for degassed water of the present invention has been described above, the present invention is not limited to the above-described embodiment and can be appropriately modified.
For example, in the present embodiment, the drain recovery tank 1 for degassed water is applied to the boiler system 100 composed of one boiler, but the present invention is not limited to this. That is, the drain recovery tank for degassed water may be applied to a boiler system composed of a plurality of boilers.

Further, in the present embodiment, the degassed water diffusion plate 50 is configured by the punching plate to supply the degassed water to the flash steam, but the present invention is not limited to this. That is, the drain recovery tank for degassed water may be configured to include a spraying device for spraying the degassed water, and the degassed water may be sprayed on the flash steam by the spraying device.

1 Drain recovery tank for degassed water 10 Tank body 11 Inspection opening 12 Overflow port 20 Mixing device 21 Inner pipe for drain introduction 22 Outer pipe for flash steam recovery 30 Flash steam exhaust part 40 Circulating water storage part 50 Degassed water diffusion Plate 90 Steam trap 91 Water supply pump 92 Supplementary water pump 93 Deoxidizer 94 Circulation pump 100 Boiler system 110 Boiler 120 Load equipment L1 Steam supply line L2 Drain introduction line L3 Degassed water supply line L4 Degassed water introduction line L5 Circulation line A Vapor phase part W Liquid phase part

Claims (3)

A degassing device provided with a mixing device formed from a tank body for storing degassed water and a double pipe of an inner pipe for drain introduction and an outer pipe for flush steam recovery by exchanging heat between the degassed water and the drain. It is a drain collection tank for steam and water.
The upper end of the drain introduction inner pipe is arranged outside the tank body, and the lower end is arranged in the gas phase part inside the tank body.
The upper end of the flash steam recovery outer pipe is arranged outside the tank body, and the lower end thereof is arranged in the liquid phase portion inside the tank body.
A drain recovery tank for degassed water provided with a circulation line for circulating degassed water of the tank body between the inner pipe for drain introduction and the outer pipe for flush steam recovery outside the tank body. The drain recovery tank for degassed water according to claim 1, further comprising a degassed water diffusion plate arranged between the inner pipe for drain introduction and the outer pipe for flush steam recovery. The drain recovery tank for degassed water according to claim 2, further comprising a flush steam exhaust unit arranged between the degassed water diffusion plate and the tank body.

Images