JP2001104942A - Method and apparatus for making degassed liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for making degassed water especially for deoxygenation capable of effectively adapted even to a method supplying nitrogen gas without increasing size of an ultrasonic treatment device to perform deoxygenation. SOLUTION: In the apparatus for making deoxygenated water, wherein gas to be degassed is mainly oxygen, being water used in an atomic power plant, a steam power plant, a food plant, a semiconductor manufacturing plant or the like, an ultrasonic treatment chamber utilizing an ultrasonic vibrator to generate no cavitation in raw water is provided on the water feed side of a degassing apparatus for supplying nitrogen gas to perform deoxygenation and raw water is modified in the ultrasonic treatment chamber to form water easy to degass and nitrogen gas is supplied to this water in the degassing device to deoxygenate the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a degassed liquid using ultrasonic waves, and more particularly to a liquid used in a nuclear power plant, a thermal power plant, a food plant, a semiconductor manufacturing facility, etc. The present invention relates to a method and an apparatus for producing a degassed liquid for removing gas, particularly oxygen, contained in water.

[0002]

2. Description of the Related Art Conventionally, in order to prevent corrosion in pipes and spoilage of food, degassing liquid producing apparatuses for removing liquids, particularly oxygen contained in water, have been widely used in plants. . As a deaerator, a method of blowing out nitrogen gas to blow out dissolved oxygen, a method of blowing out dissolved gas by heat treatment, a method of removing dissolved gas by evacuation, and the like are used for each application.

[0003] As an example, an example of a conventional deaerator for purging dissolved oxygen with nitrogen gas will be described with reference to FIG. In FIG. 5, reference numeral 1 denotes a cylindrical vessel-shaped deaeration tower;
Is a grid provided inside the degassing tower 1 for increasing the gas-liquid contact area. The grid 2 may or may not be installed by the device. Raw water 4 is sprayed into the degassing tower 1 from a spray pipe 3 installed above the grid 2 above the degassing tower 1. A nitrogen gas supply pipe 5 is provided below the lower grid 2 inside the degassing tower 1 to supply a nitrogen gas 6 into the degassing tower 1. The dissolved oxygen in the raw water 4 sprayed from the spray pipe 3 is replaced in the grid 2 or the like by contact with the nitrogen gas 6, and the dissolved oxygen is removed from the raw water 4. The degassed degassed water 8 accumulates in the lower part of the degassing tower 1, is discharged to the outside of the degassing tower via the valve 7, and is used in various plants. The gas in the degassing tower 1 is exhausted from the exhaust pipe 9.

[0004]

In various plants such as a nuclear power plant, a thermal power plant, a food plant, and a semiconductor manufacturing facility, it is necessary to treat a large amount of water to a predetermined low concentration of dissolved oxygen. For this reason, when it is not possible to deoxidize to a predetermined concentration in a single stage, a tandem system in which a plurality of degassing towers are combined is adopted, but this leads to an increase in the size of the apparatus and a prolonged degassing time. .

For this reason, it has been conventionally desired to increase the deaeration speed from the viewpoint of miniaturization of the apparatus and energy saving. In the case where a small amount of water is degassed conventionally, a method of irradiating ultrasonic waves and degassing using the action of cavitation is known as a well-known fact, but this method increases the degassing speed. However, it is known that degassing of a certain degree or more is impossible even if ultrasonic waves are irradiated no matter how long due to interfacial disturbance action (Ultrasonics Technology Handbook, page 1086, Showa 6)
August 10, 2010, 6th revised edition, Nihon Kogyo Shimbun).

Further, a method of irradiating ultrasonic waves is applied to a case where air is evacuated while evacuating.
In a system in which ultrasonic irradiation and evacuation are performed at the same time, the action of cavitation and evacuation are effective in combination, but cannot be applied to a method of supplying nitrogen gas and deoxidizing. Further, in this method, it is necessary to irradiate ultrasonic waves to the water in the entire degassing tower, and the ultrasonic processing apparatus becomes large in size, so that it is not suitable for a plant that processes a large amount of water. Therefore, the only current method is to reduce the size of water droplets or to insert the grid 2 in order to increase the gas-liquid contact area.

The present invention has been made in view of the problems of the prior art,
A method and a device for producing a degassed liquid which can be effectively applied to a method for supplying nitrogen gas and deoxidizing without increasing the size of an ultrasonic treatment device, and particularly a method for producing degassed water for deoxygenation and its method It is to provide a device.

[0008]

Means for Solving the Problems As a method for increasing the degassing rate, the present inventors have determined that water irradiated with ultrasonic waves that is weak enough not to cause cavitation has been reformed into water that is easily degassed. Heading to the present invention. That is, the invention according to claim 1 is characterized in that the raw solution is subjected to weak ultrasonic irradiation to such an extent that cavitation does not occur, reformed into a liquid that is easily degassed, and then subjected to predetermined degassing. The invention according to claim 3 relates to an apparatus for effectively carrying out the invention, wherein an ultrasonic processing chamber for applying a weak ultrasonic wave to the undiluted solution using an ultrasonic vibrator so as not to cause cavitation is provided with a deaerator. Is provided on the liquid supply side. The frequency of the ultrasonic wave is 20 KHz to 1 MH
A range of z is desirable.

Since the present invention relates to the treatment of the liquid before being supplied to the degassing apparatus, the method of the degassed liquid producing apparatus is not particularly limited. This is effective for the method and apparatus for producing degassed water. That is, the liquid is water used in a nuclear power plant, a thermal power plant, a food plant, a semiconductor manufacturing facility, and the like, and in the method for producing deoxygenated water in which the gas to be degassed is mainly oxygen, does not cause cavitation in raw water. A preferable production method can be provided by supplying a nitrogen gas and deoxygenating the water by irradiating a slightly weak ultrasonic wave to reform water to be easily degassed.

[0010] The invention according to claim 4 relates to an apparatus for effectively implementing the above-mentioned invention, and is an ultrasonic processing chamber for performing weak ultrasonic irradiation that does not cause cavitation in raw water using an ultrasonic vibrator. Is provided on the water supply side of a deaerator that supplies and deoxygenates nitrogen gas, and in the sonication chamber, after reforming into water that is easily deaerated, supplying nitrogen gas in the deaerator to perform deoxygenation. It is characterized by.

The present invention will be described in more detail with reference to the fact that water irradiated with ultrasonic waves is modified into water which is easily deoxygenated even after the ultrasonic irradiation is stopped, and retains its characteristics. People have found in experiments. Although the mechanism is not clear yet, the structure of the water molecule aggregate around the dissolved oxygen dissolved in water is destroyed by irradiating ultrasonic waves, and the dissolved oxygen is easily diffused in water. We think it may be reformed. In other words, if this effect is applied, the raw water before being supplied to the degassing device can be reformed into water that can be easily degassed simply by applying a weak ultrasonic irradiation that does not cause cavitation. The degassing speed is increased only by degassing in the same manner as the conventional method, so that the size of the apparatus can be reduced, the processing speed can be increased, and the amount of nitrogen gas can be reduced.

The present invention can be effectively applied not only to a method for supplying nitrogen gas for deoxygenation, more specifically to a large plant using a degassing tower, but also using a large degassing tower. Even if it is not necessary to irradiate ultrasonic waves to the water in the entire degassing tower, and it is sufficient to perform ultrasonic treatment on the upstream water supply passage side, a preferable apparatus configuration can be obtained without increasing the size of the apparatus, It can also be applied to plants that process large amounts of water. In addition, sufficient deaeration is possible even if the deaeration tower is made endless.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. However, unless otherwise specified, dimensions, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the invention, but are merely illustrative examples.

FIG. 1 shows an apparatus for producing a degassed liquid according to an embodiment of the present invention. Element devices indicated by reference numerals 1 to 9 in the figure have the same functions as those of the conventional apparatus for producing a degassed liquid shown in FIG. The description is omitted. Then, the raw water 4 is stored in the middle of a passage of a water supply pipe 40 which is connected to the spray pipe 3 for spraying the raw water 4 into the degassing tower 1 and supplies the raw water 4 from the previous process side. An ultrasonic treatment chamber 11 for irradiating the stored raw water 4 with a weak ultrasonic wave so as not to cause cavitation by using a probe 12;
After the water is reformed into water that is easily degassed, the reformed water is sprayed into the degassing tower 1 from the spray pipe 3 and the nitrogen gas 6 supplied from the nitrogen gas supply pipe 5 and the inside of the grid 2 or the like. It is deoxygenated by gas-liquid contact. In the figure, reference numeral 13 denotes an ultrasonic power source, which is weak enough not to cause cavitation, from 20 KHz to 1 MHz.
An ultrasonic wave having a frequency in the range of z is generated.

According to such an apparatus, the raw water 4 supplied from the water supply pipe 40 is first supplied and stored in the ultrasonic treatment chamber 11. An ultrasonic vibrator 12 is provided at the bottom of the ultrasonic processing chamber 11.
The ultrasonic vibrator 12 is driven by an ultrasonic power source 13 and the raw water 4 in the ultrasonic processing chamber 11 is irradiated with a weak ultrasonic wave that does not cause cavitation. During a certain residence time in the ultrasonic treatment chamber 11, the reformed water irradiated with ultrasonic waves is sprayed into the degassing tower 1 from the spray pipe 3, and the nitrogen gas supply pipe 5
The supplied nitrogen gas 6 is brought into gas-liquid contact with the inside of the grid 2 or the like, and subjected to a deoxygenation treatment.

Next, the results of an experiment in which it has been found that the degassing characteristics of water are improved by ultrasonic irradiation will be described with reference to FIGS. 2, 3 and 4. FIG. As shown in FIG. 2, the experiment was carried out with distilled water in a state of saturated dissolved oxygen at 25.degree.
50 cc manufactured by Wako Pure Chemical Industries, Ltd.) into a beaker 21, subjected to ultrasonic irradiation for a predetermined time in an ultrasonic cleaner 11a, and transferred the distilled water into a container 22 controlled at 25 ° C.
While stirring the solution in 3, nitrogen gas was supplied to the gas phase from the nitrogen cylinder 24, and the deoxygenation process was measured by the dissolved oxygen meter 25.

Preferably, the ultrasonic wave is irradiated with a weak ultrasonic wave which does not cause cavitation in the whole water.
In this experiment, the effect was confirmed by using an ultrasonic cleaner for a simple experiment. FIG. 3 shows the result. FIG. 3 shows the results of a deoxygenation test performed on untreated distilled water and the results of a deoxygenation test performed on distilled water irradiated with ultrasonic waves at 28 KHz × 1 minute using an ultrasonic cleaner 11a. . The liquid temperature is controlled at 25 ° C., and the liquid temperature rise due to ultrasonic irradiation is 0.2 ° C. or less.

As is apparent from FIG. 3, there is a large difference in the time-series change in the dissolved oxygen concentration between untreated distilled water and water subjected to ultrasonic irradiation for one minute. It can be seen that the waste water is reformed into water that is easily deoxygenated. In addition, when deoxidation characteristics up to a lower concentration of oxygen are required, the deoxygenation proceeds in a shorter time, so that the present invention works advantageously.

FIG. 4 shows that the frequency at the time of ultrasonic irradiation is 28 KH.
The results of a test with different irradiation times for z, 47 KHz, and 100 KHz are shown. The horizontal axis in the figure indicates the ultrasonic irradiation time, and the vertical axis indicates the time from the start of deoxidation by the above-described deoxygenation test method until the dissolved oxygen concentration reaches 0.1 [mg / 1] or less. Indicated. From this figure, it can be seen that this effect is not so much affected by the frequency of the ultrasonic wave. Therefore, the frequency is desirably 20 kHz to 1 MHz, which is cheap to handle as an ultrasonic wave.

Further, in this experiment, it can be seen that the characteristics are improved with the start of the ultrasonic irradiation, and the water is reformed into water which is easily deoxygenated by irradiation for about 1 minute. Therefore, it can be understood that the maximum effect can be expected if the volume of the ultrasonic irradiation chamber 11 is appropriately determined from the supply flow rate of the raw water 4 so that the ultrasonic irradiation time at which the deoxygenation effect is maximized is maintained.

[0021]

As described above, according to the present invention, the water such as water or oil supplied to the deaerator is irradiated with a weak ultrasonic wave which does not cause cavitation so that the water can be removed before the deaeration process. It is possible to obtain a method for reforming water that can be easily degassed by a simple method. In particular, the invention according to claim 2 or 4 can improve the deoxygenation rate, thereby increasing the dissolved oxygen concentration to a lower concentration level. The production of degassed water becomes possible. Also, in the production of degassed water with the same dissolved oxygen concentration level,
Since sufficient deaeration is possible without using a tandem structure, the deaerator can be compact, the processing speed can be improved, and the amount of nitrogen gas used can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus for producing degassed water provided with an ultrasonic treatment chamber according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing an outline of an experimental apparatus of the present invention in which an effect of promoting deoxygenation by ultrasonic irradiation has been confirmed.

FIG. 3 and FIG. 4 show experimental results of the deoxidation characteristics of untreated distilled water and distilled water subjected to ultrasonic irradiation, and FIG. 3 shows untreated distilled water and water irradiated with ultrasonic irradiation. FIG. 4 is a graph showing a time-series change in the dissolved oxygen concentration.

[Fig. 4] The frequency at the time of ultrasonic irradiation is 28KHz, 47K.
It is a graph which shows the result of having changed irradiation time with respect to 100 Hz and 100 KHz.

FIG. 5 is a configuration diagram of an apparatus for producing degassed water showing an example of a conventional deoxygenation apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Deaeration tower 2 Grid 3 Spray pipe 4 Raw water 5 Nitrogen gas supply pipe 6 Nitrogen gas 8 Deaeration water 11 Ultrasonic processing room 12 Ultrasonic transducer 13 Ultrasonic power supply 40 Water supply pipe

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kiyoshi Tatsuhara 1-8-1 Koura, Kanazawa-ku, Yokohama-shi F-term in Mitsubishi Heavy Industries, Ltd. Fundamental Technology Research Laboratories 4B021 LA42 LT03 MC04 MK01 MK13 MP01 MQ02 MQ03 4D011 AA15 AA18 AB01 AC06 AD03 4D037 AA08 AB11 BA23 BA24 BA26 BB05

Claims (4)

[Claims] 1. A method for producing a degassed liquid, comprising subjecting an undiluted liquid to weak ultrasonic irradiation that does not cause cavitation, reforming the liquid to be easily degassed, and performing a predetermined degassing. 2. A method for producing deoxygenated water, wherein the liquid is water used in a nuclear power plant, a thermal power plant, a food plant, a semiconductor manufacturing facility, and the like, and the gas to be degassed is mainly oxygen. A method for producing a degassed liquid, comprising: applying a weak ultrasonic irradiation to a degree that does not cause water generation, reforming the water to be easily degassed, and supplying nitrogen gas for deoxygenation. 3. A degassing apparatus characterized in that an ultrasonic treatment chamber for applying a weak ultrasonic wave that does not cause cavitation to the undiluted solution using an ultrasonic vibrator is provided on the liquid supply side of the deaerator. Liquid production equipment. 4. An apparatus for producing deoxidized water, wherein the liquid is water used in a nuclear power plant, a thermal power plant, a food plant, a semiconductor manufacturing facility, and the like, and the gas to be degassed is mainly oxygen. An ultrasonic treatment chamber for performing weak ultrasonic irradiation that does not cause cavitation in the raw water by using an element is provided on the water supply side of a deaerator that supplies nitrogen gas and deoxygenates. An apparatus for producing a degassed liquid, comprising supplying nitrogen gas in a degassing apparatus for deoxygenation after reforming the water into easily permeable water.