JPH07155743A - Deaeration device - Google Patents

Abstract

PURPOSE:To provide a deaeration device smaller in a scale than a conventional deaeration device and advantageous in the arrangement by utilizing an evacuation process of a nozzle. CONSTITUTION:This deaeration device consists of a tank 23 for storing water, a nozzle 21 provided on the upper part of the inside of the tank 23, pipings 25a, 25b both of whose one end are connected to a bottom of the tank 23 and their the other ends to the nozzle 21 via a pump 24, and a piping 27 to discharge gas in the tank 23 outside the tank 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deaerator for reducing the dissolved gas concentration of water in equipment and piping in industrial plants and the like.

[0002]

2. Description of the Related Art Generally, in equipment for handling water in industrial plants, oxygen in water is deaerated because corrosion occurs due to oxygen dissolved in water, for example. Methods for degassing the dissolved oxygen in the water include mechanical degassing and chemical degassing.

Chemical degassing is a method of removing dissolved oxygen with a reducing agent such as sodium sulfite and hydrazine.
When releasing the water in the equipment to the environment, it is necessary to remove the reducing agent for purification.

On the other hand, mechanical degassing is a method of extracting dissolved gas by heating or depressurizing with a vacuum pump. A conventional example of the deaerator will be described with reference to FIGS. 4 and 5. FIG. 4 shows a basic structure of a mechanical degassing device by heating. The deaerator comprises a tank 1 for storing the system water 3 and a heater 2 for heating the system water 3. By heating the system water 3 in the tank 1 with the heater 2, the solubility of the system water 3 in oxygen is lowered, and dissolved gas is deposited and released to the outside of the system for degassing.

On the other hand, FIG. 5 shows a basic structure of a deaeration device using a vacuum pump. The deaerator includes a tank 11 for storing the system water 3, a vacuum pump 13 for sucking gas existing in a space formed on the surface of the system water 3 in the tank 11 through an exhaust pipe 12a, and a vacuum pump. It is composed of an exhaust pipe 12b for exhausting from 13. The vacuum pump 13 sucks the gas in the space, reduces the pressure in the space, deposits the gas, and discharges the gas from the exhaust pipe 12b.

A concrete example of an industrial plant in which such a deaerator is considered necessary is a reactor auxiliary cooling seawater system (hereinafter referred to as RSW) of a nuclear power plant. The RSW will be described.

In a nuclear power plant, heat generated by auxiliary equipment (not shown) is removed by a reactor auxiliary equipment cooling system (hereinafter referred to as RCW), and this heat is further converted into RSW of RSW.
Heat is exchanged by a heat exchanger installed in the middle of the pipe,
Finally, it is released to the ocean through the water discharge tank. This RSW
Is a system that takes in seawater as system water, exchanges heat with RCW, and releases the warmed seawater to the ocean again. R
The SW has two 100% capacity systems,
Normally only one system is operating. One system that is idle is stored with seawater. Therefore, during this storage, marine life will be stored in the RSW pipe filled with seawater.
It adheres to the SW pipe and grows. At present, the method of diluting seawater with fresh water is used to prevent the growth of marine life, but it was not conclusive.

[0008]

The conventional deaerator described above requires a heater and a vacuum pump, and
Since auxiliary equipment for that purpose is also required, the equipment for deaeration becomes large. The present invention has been made in view of the above conventional circumstances, and an object thereof is to provide a degassing apparatus which utilizes a depressurizing process of a nozzle and is smaller in size than the conventional degassing apparatus and advantageous in terms of arrangement. Is.

[0009]

In order to achieve the above object, in the deaerator of the present invention, in the invention according to claim 1, a tank for storing water and a nozzle provided above the inside of the tank are provided. Providing a deaerator having a pipe having one end connected to the bottom of the tank and the other end connected to the nozzle via a pump, and a pipe for discharging gas in the tank to the outside of the tank Is.

According to a second aspect of the present invention, a load for deaeration is connected in the middle of a pipe whose one end is connected to the bottom of the tank and the other end is connected to the nozzle via a pump. The deaerator according to claim 1 is provided.

According to the third aspect of the present invention, there is provided a gas cylinder for supplying a gas other than the degassing target gas to the gas phase portion in the tank through a pipe to replace the inside of the tank. The deaerator according to claim 1 or claim 2 is provided.

According to a fourth aspect of the present invention, there is provided the deaerating apparatus according to the first aspect, the second aspect or the third aspect, wherein the nozzle is heated by a heater.

According to a fifth aspect of the invention, the gas in the tank is discharged to the outside of the tank by using a vacuum pump.
The deaerator described is provided.

[0014]

In the deaerator having the above structure, the water in the tank is led from the pipe connected to the bottom to the nozzle provided above the inside of the tank by the pump. Since the flow passage cross-sectional area is reduced in this nozzle, the dynamic pressure rises as the flow velocity of water increases, and the static pressure decreases because the total pressure is constant. Here, when the saturated pressure of the dissolved gas exceeds the static pressure, precipitation of the dissolved gas occurs. Degassing can be performed by discharging this dissolved gas outside the tank through a pipe.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the deaerator according to the present invention will be described below with reference to FIG. FIG. 1 shows an embodiment relating to the basic configuration of the deaerator of the present invention, which has a tank 23 for storing system water 3 and having a dissolved oxygen concentration sensor 28 at the bottom.
The system water 3 in the tank 23 is again guided from the circulation pipe 25a into the tank 23 via the transfer pump 24 and the circulation pipe 25b that pressurize the system water 3 and is discharged by the nozzle 21 provided at the tip of the circulation pipe 25b. While precipitating dissolved oxygen, it is discharged into the tank 23 as a two-phase flow with system water.

Further, the nitrogen in the nitrogen cylinder 22 is blown into the two-phase flow at the same time as it is blown into the tank 23 so that the nitrogen is supplied in the counter flow by the nitrogen supply pipe 26, and the gas phase portion 29 in the tank 23 is filled with nitrogen. The atmosphere is maintained.

The precipitated dissolved oxygen is discharged to the outside of the tank 23 by the exhaust pipe 27 connected to the gas phase portion 29 of the tank 23 together with the filled nitrogen. In the deaerator thus configured, the system water 3 is accelerated in the nozzle 21 due to the reduction of the flow passage cross-sectional area, and the flow velocity of the system water 3 is increased to increase the dynamic pressure. The static pressure of the system water 3 decreases due to the energy storage of the fluid, and a reduced pressure boiling phenomenon occurs at the throat portion of the nozzle 21 where the static pressure is minimized, and dissolved oxygen is deposited and becomes a two-phase flow and is discharged into the tank 23. To be done. Since the nitrogen in the nitrogen cylinder 22 is blown to the two-phase flow, the precipitated dissolved oxygen hardly dissolves into the system water 3 again, and the tank 23 is also maintained in the nitrogen atmosphere.
It becomes difficult to dissolve in the system water 3 even inside.

Further, in order to promote the precipitation of dissolved oxygen, for example, the nozzle 21 may be heated by a heater so that boiling in the nozzle 21 can be easily caused. Further, instead of replacing the air in the tank 23 with nitrogen, if the precipitated dissolved oxygen is released using a vacuum pump, the dissolved oxygen concentration of the system water 3 can be reduced without dissolving nitrogen in the system water 3. . Even in this case, since the heater 21 and the vacuum pump are auxiliary by providing the nozzle 21, the equipment capacity can be smaller than that of the conventional mechanical deaerator.

Next, a second embodiment of the deaerator according to the present invention will be described with reference to FIG. 2, the same parts as those in FIG. 1 are designated by the same reference numerals, and the description of the configuration will be omitted. In the present embodiment, a case is shown in which the deaerator is installed in system equipment as a load for deaerating.

The system water 3 is circulated through the system piping 36 by the system pump 37 and works in the system load 38. A dissolved oxygen concentration sensor 28 is provided in the middle of the system pipe 36. The tank 23 includes a system pipe 36, a system pump 37,
It is installed at a position higher than the system load 38. Tank 23
Is connected to a system pipe 36 through a pipe 34 and a tank stop valve 35, and further, a pipe 41 that is guided to the tank 23 through a stop valve 39 and a transfer pump 40 is connected to the system pipe 36. A nozzle 21 is provided at the tip of the pipe 41.

Further, the nitrogen in the nitrogen cylinder 22 is blown into the tank 23 at the same time as it is sprayed to this two-phase flow so that it becomes a counter flow by the nitrogen supply pipe 42 through the nitrogen supply valve 43, and the inside of the tank 23 is filled. The gas phase portion 29 is maintained in a nitrogen atmosphere.

The precipitated dissolved oxygen is discharged to the outside of the tank 23 through the exhaust valve 45 by the exhaust pipe 44 connected to the vapor phase portion 29 of the tank 23 together with the filled nitrogen. In the deaerator thus constructed, the nitrogen gas in the tank 23 is supplied to the pipe 34 when the deaerator is operated.
The system water 3 is filled up to the water level where it is not caught in the system piping 36 via. System piping 36, system pump 3
7. After applying system water 3 to system load 38, nitrogen supply valve 4
3. The exhaust valve 45 is opened, and the inside of the tank 23 is made into a nitrogen atmosphere.
Next, the tank stop valve 35 and the stop valve 39 are opened, and the transfer pump 4
0 is started, and the system water 3 in the system piping 36, the system pump 37, and the system load 38 is guided to the nozzle 21. The dissolved oxygen deposited in the nozzle 21 is discharged from the tank 23 to the exhaust pipe 4 together with nitrogen gas.
It is released via 4. In addition, the system water 3 discharged into the tank 23 flows through the tank stop valve 35 through the pipe 34 due to the head difference.
It is guided to the system pipe 36 by and is supplied again to the system pump 37 and the system load 38.

Also in this embodiment, a heater may be provided in the nozzle 21 as described in the first embodiment,
A vacuum pump may be used instead of nitrogen replacement. Furthermore, FIG. 3 shows the third embodiment of the deaerator according to the present invention.
Will be explained. In FIG. 3, the same parts as those in FIG. 1 are designated by the same reference numerals, and the description of the configuration will be omitted. In the present embodiment, as an example of the load for degassing, it is used in the reactor auxiliary cooling seawater system (hereinafter referred to as RSW) 75 of the nuclear power plant to reduce the dissolved oxygen in the seawater, and from the plant to the ocean. This is applied to prevent the growth of marine life attached to the RSW pipe 61 for discharging water. In a nuclear power plant, heat generated by auxiliary equipment (not shown) is removed by a reactor auxiliary equipment cooling system (hereinafter referred to as RCW) 76, and further by a heat exchanger 66 provided in the RSW pipe 61 of the RSW 75. It is exchanged and finally discharged to the ocean through the water stop valve 60 and the water discharge tank 62. This RSW75 takes seawater as system water and RC
It exchanges heat with W76 and releases the warmed seawater to the ocean again. The RSW75 is provided with two 100% capacity systems, and normally only one system is operated. One system that is idle is stored with seawater. Therefore, R that is filled with seawater during this storage
Marine organisms attach to the RSW pipe 61 and grow in the SW pipe 61. At present, a method of diluting seawater with fresh water is used for the purpose of inhibiting the growth of marine life, but it cannot be said to be definitive.

Therefore, the present embodiment is intended to reduce the concentration of dissolved oxygen in seawater after dilution with fresh water to make it difficult for marine organisms to breathe and to suppress the adhesion and growth to the RSW pipe 61.

In FIG. 3, RSW 75 is RSW piping 6
A RSW pump 63 is provided midway, and a heat exchanger 66 that exchanges heat with an RCW 76 is connected to the downstream side of the RSW pump 63 via a check valve 64 and a valve 65. RCW in heat exchanger 66
The system water 3 that has been removed from heat and has become hot water is discharged to the ocean through the water discharge stop valve 60 and the water discharge tank 62 as described above.

A return pipe 69 is provided in the middle of the RSW pipe 61.
Are introduced into the tank 23 through the stop valve 67 and the transfer pump 68. A nozzle 21 is provided at the end of the return pipe 69 inside the tank 23. A pipe 54 is provided at the bottom of the tank 23, and the pipe 54 is connected to the tank stop valve 35.
Is connected to the RSW pipe 61 via. Furthermore, in order to receive fresh water for filling the tank 23 from the miscellaneous water system, the water filling pipe 57 is connected to the pipe 54 at a position closer to the tank 23 than the tank stop valve 35 via the miscellaneous water stop valve 56. There is. Moreover, since the fresh water for diluting the seawater remaining in the RSW pipe 61 is supplied from the miscellaneous water system,
The dilution pipe 59 is connected to the tank stop valve 3 via the miscellaneous water stop valve 58.
It is connected to the pipe 54 at a position closer to RSW 75 than 5.

In the third embodiment of the present invention thus constructed, the RSW being operated for the purpose of inspection or the like.
When the RSW pump 63 of 75 is stopped, the RSW pipe 61 and the heat exchanger 66 on the downstream side of the RSW pump 63 are filled with seawater. In this state, the miscellaneous water stop valve 58 is opened, and fresh water from the miscellaneous water system is injected into the RSW pipe 61 through the diluting pipe 59 to make RS.
The seawater in W75 is diluted with fresh water. At this time, seawater overflowing in the RSW 75 is discharged to the water discharge tank 62.

Next, the water stop valve 60 and the miscellaneous water stop valve 58.
Is closed and the miscellaneous water stop valve 56 is opened, and water from the miscellaneous water system is filled in the tank 23 to a water level such that the nitrogen gas in the tank 23 is not caught in the pipe 54 during the operation of the deaerator. After the water filling in the tank 23 is completed, the miscellaneous water stop valve 56 is closed and the nitrogen supply valve 43 and the exhaust valve 45 are opened to make the tank 23 a nitrogen atmosphere. After that, the tank stop valve 35 and the stop valve 67 are opened, the transfer pump 68 is activated, and the seawater diluted with the fresh water in the RSW 75 is guided to the nozzle 21 through the return pipe 69. The dissolved oxygen that has become a two-phase flow in the nozzle 21 and is precipitated is discharged from the exhaust pipe 44 through the exhaust valve 45 together with nitrogen gas. The diluted seawater discharged into the tank 23 is returned to the RSW 75 due to the head difference. In this way, RS
It is possible to precipitate dissolved oxygen in the W pipe 61.

Also in this embodiment, a heater may be provided in the nozzle 21 as described in the first embodiment,
A vacuum pump may be used instead of nitrogen replacement. Therefore, according to the present embodiment, for example, it can be used together with fresh water dilution in a reactor auxiliary cooling seawater system of a nuclear power plant to suppress adhesion and growth of marine organisms to the pipe.

[0030]

As described above, in the deaerator of the present invention, the concentration of dissolved oxygen in water can be lowered and the progress of corrosion of equipment can be suppressed.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a first embodiment of a deaerator according to the present invention.

FIG. 2 is a system configuration diagram of a second embodiment of the deaerator according to the present invention.

FIG. 3 is a system configuration diagram of a third embodiment of a deaerator according to the present invention.

FIG. 4 is a system configuration diagram of a conventional deaerator using a heater.

FIG. 5 is a system configuration diagram of a conventional deaerator using a vacuum pump.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Tank 2 ... Heater 3 ... System water 11 ... Tank 12a, b ... Exhaust pipe 13 ... Vacuum pump 21 ... Nozzle 22 ... Nitrogen cylinder 23 ... Tank 24 ... Transfer pump 25a, b ... Circulation piping 26 ... Nitrogen supply piping 27 ... Exhaust pipe 28 ... Dissolved oxygen concentration sensor 29 ... Gas phase part 34 ... Piping 35 ... Tank stop valve 36 ... System piping 37 ... System pump 38 ... System load 39 ... Stop valve 40 ... Transfer pump 41 ... Piping 42 ... Nitrogen supply piping 43 ... Nitrogen supply valve 44 ... Exhaust pipe 45 ... Exhaust valve 54 ... Piping 56 ... Miscellaneous water stop valve 57 ... Water filling pipe 58 ... Miscellaneous water stop valve 59 ... Diluting pipe 60 ... Water discharge stop valve 61 ... RSW piping 62 ... Water discharge tank 63 ... RSW pump 64 ... Check valve 65 ... Valve 66 ... Heat exchanger 67 ... Stop valve 68 ... Transfer pump 69 ... Return piping 75 ... Reactor auxiliary equipment cooling seawater system 76 ... Reactor auxiliary equipment cooling system

Claims (5)

[Claims] 1. A tank for storing water, a nozzle provided above the inside of the tank, a pipe having one end connected to the bottom of the tank and the other end connected to the nozzle via a pump, A degassing device comprising: a pipe for discharging the gas in the tank to the outside of the tank. 2. A degassing load is connected in the middle of a pipe, one end of which is connected to the bottom of the tank and the other end of which is connected to the nozzle via a pump. Deaerator. 3. A gas cylinder for supplying a gas other than a gas to be degassed to the gas phase portion in the tank through a pipe to replace the gas in the tank.
The deaerator described. 4. The deaerator according to claim 1, 2, or 3, wherein the nozzle is heated by a heater. 5. The gas in the tank is discharged to the outside of the tank by using a vacuum pump.
Alternatively, the deaeration device according to claim 3 or claim 4.