JP2885997B2 - Degassing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deaerator for removing dissolved oxygen in water, and more particularly to the present invention for use in the production of pure water used in semiconductor production, boilers, pharmaceutical production and the like. It relates to a deaerator.

[0002]

2. Description of the Related Art Conventionally, in the production of pure water, dissolved oxygen in water has been removed for the purpose of preventing corrosion of boilers and generation of bacteria.

FIG. 5 shows an example of the configuration of a conventional deaerator, in which 50 is a raw water tank. Raw water is inflow pipe 5
From 1, the raw water enters a raw water tank 50, where it is appropriately stored, and then sent to the top of a degassing tower 53 through a water pipe 52.
Reference numeral 54 denotes a water pump. Next, the raw water sent to the top of the tower flows down in the degassing tower.

Reference numeral 55 denotes a supply pipe for supplying an inert gas such as nitrogen gas. The nitrogen gas supplied to the bottom of the tower from the supply pipe 55 is brought into gas-liquid contact with the raw water in a countercurrent manner when passing through the inside of the tower 53. To remove the dissolved oxygen in the raw water, and discharged from the tower through the waste gas pipe 56 to the atmosphere. On the other hand, the raw water from which dissolved oxygen has been removed in the tower is taken out from the tower bottom through the outflow pipe 57 and becomes treated water. Reference numeral 58 denotes an outflow pump.

[0005] In this case, in order to obtain treated water of a low concentration of dissolved oxygen, the amount of nitrogen gas to be aerated must be increased, or the height of the tower or the diameter of the tower must be increased to prolong the gas-liquid reaction time. Were required, but all were uneconomical.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to effectively utilize an inert gas such as nitrogen gas discharged from a tower top.
An object of the present invention is to provide a deaerator capable of efficiently removing dissolved oxygen in raw water.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a raw water tank for storing raw water to be deaerated, supplying the raw water in the raw water tank to the top of the raw water tank, and removing the raw water from the bottom of the tower. A deaerator for removing dissolved oxygen in raw water comprising a degassing tower for supplying an active gas and performing gas-liquid contact in the tower, wherein the inert gas discharged from the top of the raw water tank It is equipped with a feed pipe for feeding to the lower side of the inside, and the inert gas discharged from the top of the tower is blown into the raw water in the raw water tank to reduce the dissolved oxygen of the raw water in the raw water tank in advance. Including that the supply pipe is provided with an inert gas supply means, that the supply means is an air pump, and that the supply pipe is an ejector provided in an inflow pipe for flowing raw water into the raw water tank.

The inert gas supply means is not limited to the above-described air pump and ejector, but may be, for example, a blower or the like.

In the present invention, the used inert gas is introduced into the raw water tank through a pipe from the top of the tower and aerated, and the inert gas contains a small amount of oxygen. There is no problem in reducing dissolved oxygen.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.
In the figure, reference numeral 11 denotes a raw water inflow pipe through which raw water from which dissolved oxygen is to be removed flows into a raw water tank 12. The raw water in the tank 12 flows through the water pipe 13 into the top 15 of the degassing tower 14. Reference numeral 16 denotes a water supply pump interposed in the water supply pipe 13. The degassing tower 14 may be of any structure as long as gas and liquid are sufficiently contacted in the tower. For example, a packed tower filled with various fillers such as Raschig rings, a column tower, or the like can be appropriately used.

The raw water sent to the tower top 15 flows down in the tower and reaches the tower bottom 17. During this time, the raw water comes into gas-liquid contact with an inert gas described later, whereby dissolved oxygen is inertized from the raw water. Dissolved oxygen is converted into treated water from which the dissolved oxygen is sufficiently removed before moving into the gas and reaching the bottom 17. This treated water is taken out from an outlet pipe 18 at the bottom 17 by an outlet pump 19.
On the other hand, 20 is an inert gas supply pipe, which passes through this supply pipe,
An inert gas such as nitrogen is supplied to the column bottom 17 and moves to the column top 15 while making gas-liquid contact in the column as described above. The inert gas that has reached the tower top 15 passes through a feed pipe 21 communicating with the inside of the raw water tank 12 and is blown into the raw water at the lower side inside the raw water tank 12. Reference numeral 22 denotes a dispersion plate, whereby nitrogen gas is blown into the raw water as fine bubbles, rises in the raw water while efficiently removing dissolved oxygen in the raw water, and is discharged out of the system. Reference numeral 23 denotes a liquid dispersion mechanism.

FIG. 2 shows another embodiment of the present invention.

In this embodiment, an ejector 24 is interposed in the raw water inflow pipe 11, and the other end of the feed pipe 21 having one end connected to the top 15 is connected to a suction part of the ejector 24. Since other configurations are the same as those of the above-described embodiment, the same portions are denoted by the same reference numerals and description thereof will be omitted.

In such a configuration, the raw water is supplied to the inflow pipe 1.
After flowing through 1, the suction part of the ejector 24 becomes negative pressure, and therefore, the pressure in the degassing tower 14 is reduced, thereby increasing the oxygen removing effect in the degassing tower 14.

When an ejector is used as the inert gas supply means as in this embodiment, gas-liquid contact between the raw water and the inert gas is sufficiently performed in the ejector.
The dispersion plate 22 in FIG. 2 may be omitted.

FIG. 3 shows still another embodiment of the present invention.

This embodiment is the same as the embodiment shown in FIG. 1 except that an air pump 25 is interposed in the feed pipe 21. By sending the inert gas at the tower top 15 to the raw water tank 12 by the air pump 25, the pressure inside the tower is reduced, whereby the oxygen removing effect in the degassing tower 14 is enhanced.

FIG. 4 shows still another embodiment of the present invention.

In this embodiment, the discharge side of the water supply pump 16 and the raw water inlet side of the ejector 24 are connected by a return pipe 26, and a part of the discharge water of the water supply pump 16 is returned to the raw water inlet side of the ejector 24. Have been. For this reason, the ejector 24
Increases the amount of raw water passing therethrough, increasing the suction force of the ejector 24, and as a result, further reducing the pressure in the degassing tower 14. Thereby, the oxygen removing effect of the degassing tower 14 is further enhanced.

As shown in the above embodiment, the raw water tank has some water depth, and if nitrogen gas or the like is directly blown, the water head becomes back pressure and is applied to the deaeration tower. If the pressure of the degassing tower is reduced to atmospheric pressure or lower by suctioning and injecting nitrogen gas or installing an air pump or the like, the dissolved oxygen value of the treated water is further remarkably reduced.

[0022]

The present invention will be specifically described below with reference to examples and comparative examples. (Examples 1 to 3 and Comparative Example 1) Degassing treatment of raw water was performed using the embodiment shown in FIGS. 1 to 3 (Examples 1 to 3) and the embodiment shown in FIG. 5 (Comparative Example). Table 1 shows the operating conditions of the deaerator.

The results obtained are shown in Table 2.

[0024]

[Table 1]

[0025]

[Table 2] As is clear from the above embodiment, by blowing the waste gas containing the residual N ₂ gas into the raw water tank, the dissolved oxygen concentration of the treated water can be reduced as compared with the conventional case, and in addition to this, an ejector and an air pump When the internal pressure of the tower is lowered by suction or the like, the effect of reducing the dissolved oxygen concentration is more remarkable.

[0026]

According to the present invention, even if the same amount of nitrogen gas as before is used, there is an effect of improving the dissolved oxygen concentration of the treated water. Gas consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing another example of the embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing still another example of the embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing still another example of the embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing an example of a conventional deaerator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Raw water inflow pipe 12 Raw water tank 13 Water pipe 14 Degassing tower 15 Tower top 16 Water pump 17 Tower bottom 18 Outflow pipe 19 Outflow pump 20 Inert gas supply pipe 21 Feed pipe 22 Dispersion plate 23 Liquid dispersion mechanism 24 Ejector 25 Air pump

Claims (4)

(57) [Claims] 1. A raw water tank for storing raw water to be degassed, and raw water in the raw water tank is supplied to the top of the tower and an inert gas is supplied from the bottom of the raw water tank to perform gas-liquid contact in the tower. A deaerator for removing dissolved oxygen in raw water comprising a deaerator and a feed pipe for feeding an inert gas discharged from the top to a lower side in the raw water tank, A degassing device characterized in that dissolved oxygen in raw water in a raw water tank is previously reduced by blowing inert gas discharged from the top into raw water in a raw water tank. 2. The degassing apparatus according to claim 1, wherein an inert gas feeding means is provided in the feeding pipe. 3. The degassing device according to claim 2, wherein the feeding means is an air pump. 4. The deaerator according to claim 2, wherein the feeding means is an ejector interposed in an inflow pipe for flowing raw water into the raw water tank.