Dissolved oxygen removal device and method

Abstract

To provide a device for removing dissolved oxygen more easily, and inexpensively while exerting superior deaeration efficiency without increasing in size and cost of the device and provide a method of removing dissolved oxygen.SOLUTION: A device for removing dissolved oxygen is characterized by including: a liquid supply line 3 supplying a liquid to a fine bubble generator 2; a gas supply line 4 supplying an optional gas having the oxygen content rate of 10 vol% or less to the fine bubble generator; the fine bubble generator generating a fine bubble-containing liquid by making the liquid contain the above gas as a fine bubble; a separation vessel 5 separating a dissolved oxygen in the fine bubble-containing liquid; and a separation liquid supply line 6 connected to the separation vessel and supplying to outside, a separation liquid in which the above oxygen is separated.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an oxygen removal device and an oxygen removal method for removing oxygen dissolved in liquids such as beverages by using microbubbles. [Background technology]

[0002] Conventionally, as a method for removing dissolved oxygen from liquids, there is known a "deoxygenation method for removing dissolved oxygen from a process liquid used in an industrial process, in which vaporized liquefied nitrogen gas is ejected into a process liquid delivery path to form minute nitrogen gas bubbles in the process liquid, and the process liquid is then made into a supersonic gas-liquid mixed fluid, and the oxygen dissolved in the process liquid is absorbed into the nitrogen bubbles" (Patent Document 1).

[0003] Furthermore, a method for producing a beverage using fine bubbles is known, which includes "a first deaeration step of deaeration of the beverage to reduce the dissolved gas concentration, a nitrogen bubble generation step of generating ultrafine bubbles using nitrogen gas in the deaerated beverage, and a heat sterilization step of heat sterilizing the beverage containing the ultrafine bubbles generated by nitrogen gas" (Patent Document 2).

[0004] These methods enable degassing treatment to be performed more efficiently than existing degassing methods. However, these methods have problems such as the need to convert the process water into a supersonic gas-liquid mixed fluid and the need to use another dissolved oxygen removal device in combination with a fine bubble generator, resulting in large equipment and high costs. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-184811 [Patent Document 2] JP 2018-102293 A Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the above-mentioned conventional drawbacks, the present invention aims to provide a dissolved oxygen removal device and method that are simpler, lower cost, and have excellent degassing efficiency without requiring a large and expensive device. [Means for solving the problem]

[0007] In order to achieve the above object, a dissolved oxygen removal device according to claim 1 of the present invention includes a liquid supply line for supplying a liquid to a fine-bubble generating device, a gas supply line for supplying an arbitrary gas having an oxygen content of 10 vol % or less to the fine-bubble generating device, the fine-bubble generating device for generating a fine-bubble-containing liquid by causing the gas to be contained in the liquid as fine bubbles, a separation container for separating the dissolved oxygen in the fine-bubble-containing liquid, and a separated liquid supply line connected to the separation container for supplying the separated liquid from which the dissolved oxygen has been separated to the outside, and the fine-bubble generating device is configured to separate the gas and the liquid from the liquid, a mixed fluid supply line that supplies the mixed fluid mixed in the mixer to a plurality of nozzle sections; a booster pump that pressurizes at least the liquid supplied from the liquid supply line or the mixed fluid mixed in the mixer; and the plurality of nozzle sections that are connected to the mixed fluid supply line and are provided in parallel within the liquid in the separation container, and that spray and shear the pressurized mixed fluid to generate fine bubbles, wherein the fine bubbles have a mode particle size of 1000 nm or less in a particle size distribution based on the number of particles.

[0008] The dissolved oxygen removal device according to claim 2 is characterized in that the concentration of the microbubbles contained in the microbubble-containing liquid is 150 million bubbles / mL or more.

[0009] The dissolved oxygen removal apparatus according to claim 3 further comprises a circulation line through which the micro-bubble-containing liquid in the separation vessel circulates, the circulation line including a circulation pipeline, a circulation pump provided midway through the circulation pipeline, and a throttle section provided in the circulation pipeline.

[0010]

[0011] The liquid in the dissolved oxygen removal device according to claim 4 is a beverage. The liquid in the dissolved oxygen removal device according to claim 5 is characterized in that it is boiler water. The method for removing dissolved oxygen according to claim 6 includes a liquid supplying step of supplying a liquid to a fine-bubble generating device, a gas supplying step of supplying an arbitrary gas having an oxygen content of 10 vol % or less to the fine-bubble generating device, a fine-bubble-containing liquid producing step of causing the gas supplied in the gas supplying step to be contained as fine bubbles in the liquid supplied in the liquid supplying step, and a dissolved oxygen removing step of removing oxygen dissolved in the fine-bubble-containing liquid produced in the fine-bubble-containing liquid producing step, the fine-bubble generating device including a mixer for mixing the gas and the liquid, a mixed fluid supply line for supplying the mixed fluid mixed in the mixer to a plurality of nozzles, and at least Liquid Supply Line and the plurality of nozzle units, which are connected to the mixed fluid supply line and are provided in parallel within the liquid in the separation container, for injecting and shearing the pressurized mixed fluid to generate fine bubbles, wherein the fine bubbles have a mode particle size of 1000 nm or less in a particle size distribution based on the number of particles.

[0012] The method for removing dissolved oxygen according to claim 7 is characterized in that the concentration of the microbubbles contained in the microbubble-containing liquid is 150 million bubbles / mL or more. The dissolved oxygen removal step of the dissolved oxygen removal method according to claim 8 is characterized in that a circulation step is performed in which the micro-bubble-containing liquid is circulated so that the dissolved oxygen concentration in the micro-bubble-containing liquid is equal to or lower than a predetermined concentration. The method for removing dissolved oxygen according to a ninth aspect of the present invention is characterized in that the liquid is a beverage. The method for removing dissolved oxygen according to claim 10 is characterized in that the liquid is boiler water. Effect of the Invention

[0013] As is clear from the above description, the present invention provides the following effects. (1) In each of the inventions described in claims 1 and 6, by adding any gas having an oxygen content of 10 vol % or less in the form of fine bubbles to the liquid, more efficient deoxidation treatment can be achieved. (2) By using fine bubbles with a mode particle size of 1,000 nm or less in the particle size distribution based on the number of bubbles, the speed at which the bubbles rise to the water surface can be greatly slowed, thereby reducing the amount of gas used. (3) The inventions recited in claims 2 and 7 also provide the same effects as those of the above (1) and (2), and can further increase the efficiency of the deoxidation process by increasing the concentration of fine bubbles. (4) The inventions described in claims 3 and 8 can obtain the same effects as those described in (1) to (3) above, and can also circulate the liquid with a reduced dissolved oxygen concentration to further incorporate fine bubbles and perform deoxidation treatment. Therefore, the oxygen concentration in the liquid can be further reduced. (5) The inventions recited in claims 4 and 9 also provide the same effects as those of the above (1) to (4), and can perform deoxidation treatment with low risk in terms of food hygiene. (6) The inventions described in claims 5 and 10 have the same effects as those described in (1) to (4) above, and can also prevent corrosion of the boiler by removing dissolved oxygen. [Brief description of the drawings]

[0014] 1 to 6 are explanatory diagrams showing a first embodiment of the present invention. 7 and 8 are explanatory diagrams showing a second embodiment of the present invention. 9 and 10 are explanatory diagrams showing a third embodiment of the present invention. [Figure 1] FIG. 1 is a schematic explanatory diagram of a dissolved oxygen removal device according to a first embodiment. [Diagram 2] FIG. 2 is an explanatory diagram of a microbubble generating device. [Diagram 3] Reference explanatory diagrams showing the inclination of the nozzle parts. (a) An explanatory diagram when both opposing nozzle parts are inclined at 0°. (b) An explanatory diagram when one of the opposing nozzle parts is inclined at 40°. (c) An explanatory diagram when the opposing nozzle parts are inclined at 20° in different directions and the fluids sprayed from the opposing nozzle parts collide at an inclination of 40°. [Figure 4] FIG. 1 is a reference explanatory diagram showing the arrangement of nozzle parts. (a) An explanatory diagram when the opposing nozzle parts are arranged so that their central axes are coaxial (0 mm apart). (b) An explanatory diagram when the opposing nozzle parts are arranged so that their central axes are 100 mm apart (100 mm apart). [Diagram 5] 1 is a table showing the relationship between microbubble concentration and dissolved oxygen concentration. [Figure 6] FIG. 2 is a process diagram of the dissolved oxygen removal method according to the first embodiment. [Figure 7] FIG. 5 is a schematic explanatory diagram of a dissolved oxygen removal device according to a second embodiment. [Figure 8] FIG. 4 is a process diagram of a method for removing dissolved oxygen according to a second embodiment. [Figure 9] FIG. 11 is a schematic explanatory diagram of a dissolved oxygen removal device according to a third embodiment. [Figure 10] FIG. 11 is a process diagram of a method for removing dissolved oxygen according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. In a first embodiment for carrying out the present invention shown in Figs. 1 to 6, reference numeral 1 denotes a dissolved oxygen removal device that removes dissolved oxygen mainly from liquids such as beverages by using fine bubbles of the present invention, so-called microbubbles or ultrafine bubbles (UFB, bubbles having a diameter of 1 µm or less).

[0016] As shown in FIG. 1, this dissolved oxygen removal device 1 includes a liquid supply line 3 for supplying liquid to a fine-bubble generator 2, a gas supply line 4 for supplying an arbitrary gas having an oxygen content of 10 vol % or less to the fine-bubble generator 2, the fine-bubble generator 2 for causing the liquid supplied from the liquid supply line 3 to contain, as fine bubbles, the arbitrary gas having an oxygen content of 10 vol % or less supplied from the gas supply line 4, thereby generating a fine-bubble-containing liquid, a separation container 5 for separating dissolved oxygen in the fine-bubble-containing liquid generated by the fine-bubble generator 2, and a separated liquid supply line 6 connected to the separation container 5 for supplying the separated liquid from which the dissolved oxygen has been separated to the outside.

[0017] The liquid supply line 3 is a line that transfers the liquid supplied from a liquid supply source 7 to the micro-bubble generator 2 .

[0018] The liquid supply source 7 supplies a liquid in which gas is to be contained in the form of fine bubbles, and this liquid is preferably a beverage such as drinkable water or a soft drink.

[0019] Furthermore, if dissolved oxygen is present in the boiler water, it can prevent the formation of a protective film or cause pitting corrosion due to the formation of oxygen concentration cells, etc. Since the dissolved oxygen in the boiler water thus affects the corrosion of the boiler, it is also effective to supply boiler water as a liquid from liquid supply source 7 and remove the dissolved oxygen in the boiler water.

[0020] This liquid supply source 7 may be a tank in which liquid is stored, or in the case of water, a water pipe or a water storage tank, or other liquid supply source 7 may be a purified water storage tank that has been purified from lake water, well water, river water, or seawater through a water purification device.

[0021] The gas supply line 4 is a line for sending any gas having an oxygen content of 10 vol % or less, which is supplied from a gas supply source 8, to the fine bubble generator 2. The gas supply source 8 is preferably a tank, a cylinder, or in the case of air, a compressor.

[0022] In this embodiment, nitrogen gas is used as the gas that produces the fine bubbles, but it is also possible to use a rare gas or a gas such as air whose gas composition ratio has been changed by PSA or the like to have an oxygen content of 10 vol% or less.

[0023] The micro-bubble generator 2 is connected to a liquid supply line 3 and a gas supply line 4, and mixes the supplied gas with the liquid so that the liquid contains micro-bubbles, thereby generating a micro-bubble-containing solvent, which is then sent to a separation vessel 5 (secondary side).

[0024] As shown in FIG. 2, in this embodiment, the fine-bubble generating device 2 is composed of a mixer 9 that mixes the liquid supplied from the liquid supply line 3 and the gas supplied from the gas supply line 4, a mixed fluid supply line 11 that supplies the mixed fluid mixed in the mixer 9 to a plurality of nozzle units 10, a booster pump 12 that pressurizes at least the liquid supplied from the liquid supply line 3 or the mixed fluid mixed in the mixer 9, and the plurality of nozzle units 10 that are connected to the mixed fluid supply line 11 and are provided in parallel within the liquid in the separation container 5, and generate fine bubbles by spraying and shearing the pressurized mixed fluid.

[0025] In this embodiment, the separation container 5 is one of the elements constituting the fine-bubble generating device 2. However, the separation container 5 may be provided separately from the fine-bubble generating device 2.

[0026] The mixer 9 is connected to the liquid supply line 3 and the gas supply line 4, and mixes the supplied gas and liquid in the mixer 9 and sends the mixture to the secondary side (the separation vessel 5 side). The mixed fluid mixed in the mixer 9 is in a state in which gas bubbles are contained in the liquid supplied from the liquid supply line 3 .

[0027] The mixed fluid supply line 11 is a line that connects the secondary side of the mixer 9 to the multiple nozzle portions 10, and in this embodiment, a boost pump 12 is provided on this mixed fluid supply line 11.

[0028] In this embodiment, the boost pump 12 is provided on the secondary side of the mixer 9, i.e., between the mixer 9 and the separation vessel 5 in the mixed fluid supply line 11, and boosts the mixed fluid to at least 0.3 MPa or more.

[0029] The boost pump 12 used may be any type that can boost and pump the liquid, and any known boost pump for liquids may be used.

[0030] As described above, it is desirable for the pressure of the liquid or mixed fluid after being pressurized by the boost pump 12 to be 0.3 MPa or more, but ultra-fine bubbles can be generated even if the pressure is less than 0.3 MPa.

[0031] In this embodiment, the separation container 5 is a container-shaped member capable of holding a liquid such as a liquid inside. A tubular discharge part 13, for example, is connected to the upper side of the separation container 5, and after the liquid containing fine bubbles is produced inside the separation container 5, oxygen degassed from the liquid containing fine bubbles is discharged to the outside from the discharge part 13.

[0032] As shown in Figs. 3 and 4, the nozzle portions 10 are provided side by side so that the mixed fluid sprayed from the nozzle portions 10 is sheared, and preferably are disposed substantially opposite each other. Here, the juxtaposed state includes a substantially opposing state, which includes a state in which the nozzle portions 10 face each other with their central axes positioned on the same line, and a state in which the nozzle portions 10 are positioned opposite each other with their central axes spaced apart.

[0033] In this embodiment, the nozzles 10 are disposed in an approximately opposing relationship, and when the mixed fluid pressurized to a predetermined pressure and supplied from the mixed fluid supply line 11 is sprayed from the nozzle 10, the mixed fluid is put into a sheared state, and ultra-fine bubbles are generated in the liquid in the separation container 5.

[0034] Specifically, the nozzle portions 10 are disposed substantially opposite each other including on a straight line, and the spray direction can be tilted at an angle of 0° to 40° as shown in Fig. 3. Here, 0° is the angle at which the central axis of one nozzle portion 10 and the central axis of the other nozzle portion 10 facing this nozzle are coaxial or parallel, and the nozzle portions are provided so as to be tiltable up to 40° in plus or minus directions (up and down directions in the drawing) from this 0°.

[0035] It is desirable to adjust this angle so that the angle between opposing nozzle portions 10 is a maximum of 40°; for example, when the inclination of one nozzle portion 10 is 0°, it is desirable to adjust the angle of the other nozzle portion 10 to a maximum of 40° (40° in the vertical direction), and when the inclination of one nozzle portion 10 is 20°, it is desirable to adjust the angle of the other nozzle portion 10 so that it is inclined in the opposite direction to the first nozzle portion 10 and is a maximum of 20°. That is, the angle of the opposing nozzle portions 10 is set so that the mixed fluids sprayed from the opposing nozzle portions 10 collide with each other at an inclination of a maximum of 40°.

[0036] In addition, the multiple nozzle units 10 facing each other can be installed at a distance of 0 mm to 100 mm from their respective central axes, as shown in Fig. 4. In other words, the nozzle units 10 are disposed facing each other and offset from a straight line aligned with their central axes by a distance in the range of 0 mm to 100 mm.

[0037] With this arrangement, the mixed fluids sprayed from the nozzle portion 10 collide with or come close to each other, and are efficiently sheared, thereby efficiently generating ultra-fine bubbles.

[0038] Incidentally, the maximum flow velocity of the mixed fluid passing through the nozzle portion 10 at this time is preferably 10 m / sec to 200 m / sec, and more preferably 50 m / sec to 150 m / sec.

[0039] If the particle size of the fine bubbles contained in the fine bubble-containing liquid is sufficiently small, the total surface area of ​​the bubbles increases, and the dissolved oxygen in the liquid can be efficiently removed.

[0040] Furthermore, in gas replacement by bubbling with bubbles having a large diameter, the contact time between the gas supplied from the gas supply source 8 (nitrogen gas in this embodiment) and the liquid is short, so the bubbles burst at the liquid surface before the gas supplied from the gas supply source 8 has fully absorbed oxygen, resulting in a large amount of gas used from the gas supply source 8. By reducing the bubble diameter to the ultra-fine bubble range, the speed at which the bubbles rise to the water surface becomes extremely slow, making it possible to reduce the amount of gas used supplied from the gas supply source 8.

[0041] In order to obtain such an effect, the most frequent particle size in the particle size distribution based on the number of fine bubbles is preferably smaller than 1000 nm, and more preferably smaller than 500 nm.

[0042] Furthermore, as shown in FIG. 5, the higher the volume ratio of gas per fixed volume of fine bubbles in the fine bubble-containing liquid (the higher the concentration), the higher the efficiency of degassing the dissolved oxygen in the liquid.

[0043] When the liquid is a beverage, the dissolved oxygen is preferably 1 ppm or less, and the content of microbubbles contained in the microbubble-containing liquid generated by the microbubble generator 2 is preferably 150 million or more per mL of the liquid. In this embodiment, nitrogen gas is used, which also enhances safety.

[0044] In the separation vessel 5 of the micro-bubble generator 2, the micro-bubble-containing liquid is left to stand and an operation for removing the dissolved oxygen from the micro-bubble-containing liquid is performed. The oxygen dissolved in the micro-bubble-containing liquid is adsorbed by the nitrogen gas in the form of micro-bubbles, floats above the liquid, and is discharged to the outside from the discharge part 13 provided in the separation vessel 5.

[0045] In this embodiment, a circulation line 14 is provided through which the fine bubble-containing liquid stored in the separation container 5 circulates. The circulation line 14 is composed of a circulation pipe 15 that connects the separation container 5 or the separation liquid supply line 6 to the liquid supply line 3, a circulation pump 16 provided midway through the circulation pipe 15, and a throttle section 17 that adjusts the flow rate in the circulation pipe 15.

[0046] By providing this circulation line 14, the liquid (fine-bubble-containing liquid) in the separation vessel 5 can be returned to the liquid supply line 3 (upstream of the mixer 9) and circulated, and the fine-bubble-containing liquid with a reduced dissolved oxygen concentration can be circulated and further mixed with gas to contain a high concentration of fine bubbles, thereby further reducing the dissolved oxygen concentration in the liquid. In addition, the concentration of fine bubbles can also be efficiently increased.

[0047] The circulation line is provided with a throttle section 17, and the flow rate of the liquid containing fine bubbles can be adjusted by changing the opening degree of this throttle section 17, thereby adjusting the concentration of dissolved oxygen in the liquid containing fine bubbles.

[0048] The separation solution from which dissolved oxygen has been removed is supplied to the outside through a separation liquid supply line 6 connected to the separation container 5. It is preferable to provide this separation liquid supply line 6 with a gate valve 18.

[0049] As shown in FIG. 6, the dissolved oxygen removal method 19 of the present invention includes a liquid supplying process 20 for supplying a liquid to a fine-bubble generating device 2, a gas supplying process 21 for supplying an arbitrary gas having an oxygen content of 10 vol.% or less to the fine-bubble generating device 2, a fine-bubble-containing liquid producing process 22 for causing the arbitrary gas having an oxygen content of 10 vol.% or less supplied in the gas supplying process 21 to be contained as fine bubbles in the liquid supplied in the liquid supplying process 20, and a dissolved oxygen removing process 23 for removing oxygen dissolved in the fine-bubble-containing liquid produced in the fine-bubble-containing liquid producing process 22.

[0050] The liquid supplying process 20 is a process of supplying liquid from the liquid supply source 7 to the fine-bubble generating device 2 via the liquid supplying line 3. Although various liquids are possible, in this embodiment, a beverage such as water or a soft drink is used as the liquid.

[0051] In the gas supply process 21, gas is supplied from the gas supply source 8 to the fine bubble generator 2 via the gas supply line 4. Any gas with an oxygen content of 10 vol% or less is used as the gas to be supplied, and in this embodiment, nitrogen gas is used. Note that gas such as rare gas or air whose gas composition ratio has been changed to an oxygen content of 10 vol% or less by PSA or the like can also be used.

[0052] The liquid supplying step 20 and the gas supplying step 21 are carried out substantially simultaneously, but either one of the steps may be carried out first.

[0053] In the microbubble-containing liquid production step 22, a microbubble generating device 2 is used to cause the liquid to contain gas in the form of microbubbles, thereby producing a microbubble-containing liquid.

[0054] In the dissolved oxygen removal process 23, the microbubble-containing liquid is stored in the separation container 5, and the dissolved oxygen is adsorbed by the microbubbles, so that the dissolved oxygen concentration of the microbubble-containing liquid is reduced to a predetermined concentration or less. In this embodiment, the separation container 5 and the container for producing the microbubble-containing liquid are the same, so the dissolved oxygen removal process 23 is started approximately simultaneously with the microbubble-containing liquid production process 22.

[0055] The dissolved oxygen concentration of the microbubble-containing liquid will vary depending on the liquid. For example, in the case of a beverage, it is desirable to have a dissolved oxygen concentration of 1 ppm or less. Microbubbles are added to the liquid so that the dissolved oxygen concentration is below this level, and the dissolved oxygen is separated in a separation vessel.

[0056] In this embodiment, in the dissolved oxygen removal step 23, a circulation step 24 is performed in which the liquid in the separation vessel 5 is circulated through the circulation line 14 to reduce the dissolved oxygen concentration.

[0057] In this circulation step 24, the dissolved oxygen is separated in the separation vessel 5, and the micro-bubble-containing liquid with a reduced dissolved oxygen concentration is circulated to the liquid supply line 3, where the gas is mixed again in the mixer 9 and sprayed from the nozzle portion 10. By thus allowing the micro-bubble-containing liquid with a reduced dissolved oxygen concentration to further contain a high concentration of micro-bubbles, the dissolved oxygen concentration can be further reduced.

[0058] The separated liquid, the dissolved oxygen concentration of which has been reduced to a predetermined level or lower in the dissolved oxygen removal step 23, is supplied to the outside via a separated liquid supply line 6 or the like.

[0059] [Different modes for carrying out the invention] Next, different embodiments for carrying out the present invention will be described with reference to Figures 7 to 10. In describing these different embodiments for carrying out the present invention, the same components as those in the first embodiment for carrying out the present invention are designated by the same reference numerals, and duplicated descriptions will be omitted.

[0060] The second embodiment of the present invention shown in Figs. 7 and 8 mainly differs from the first embodiment of the present invention in that a known fine-bubble generator 2A is used, and a dissolved oxygen removal device 1A is used to supply fine-bubble-containing liquid to a separation vessel 5 via a fine-bubble-containing liquid supply line 25 connected to the fine-bubble generator 2A, and a dissolved oxygen removal method 19A is used to perform a dissolved oxygen removal step 23A in which dissolved oxygen is removed in a separation vessel 5 independent of the fine-bubble generator 2A after the fine-bubble-containing liquid production step 22. Such dissolved oxygen removal device 1A and dissolved oxygen removal method 19A can provide the same effects as those of the first embodiment of the present invention.

[0061] In addition, the separation container 5 of this embodiment is capable of storing a micro-bubble-containing liquid that has had micro-bubbles added thereto by the micro-bubble generating device 2A, and performs deoxidation by causing the micro-bubbles to adsorb dissolved oxygen, and no nozzle portion 10 or the like is provided inside this separation container 5.

[0062] The second embodiment of the present invention shown in FIGS. 9 and 10 differs from the first embodiment of the present invention mainly in that a known fine bubble generator 2A is used, a dissolved oxygen removal apparatus 1B does not have a circulation line 14, and a dissolved oxygen removal method 19B includes a dissolved oxygen removal step 23B that does not perform a circulation step 24. Such dissolved oxygen removal apparatus 1B and dissolved oxygen removal method 19B can provide the same effects as those of the first embodiment of the present invention. [Industrial Applicability]

[0063] The present invention is applicable to industries that use fine bubbles to remove dissolved oxygen from liquids. [Explanation of symbols]

[0064] 1, 1A, 1B: Dissolved oxygen device, 2, 2A: Microbubble generator, 3: liquid supply line; 4: gas supply line; 5: Separation vessel 5: Separation liquid supply line, 7: liquid supply source; 8: gas supply source; 9: mixer; 10: nozzle portion; 11: mixed fluid supply line; 12: boost pump; 13: discharge section; 14: circulation line; 15: circulating line; 16: circulating pump; 17: throttle portion; 18: gate valve; 19, 19A, 19B: Dissolved oxygen removal method, 20: liquid supply step; 21: gas supply step; 22: Microbubble-containing liquid generating step; 23, 23A, 23B: Dissolved oxygen removal process, 24: Circulation process; 25: Microbubble-containing liquid supply line.

Claims

1. The present invention includes a liquid supply line for supplying a liquid to a fine-bubble generating device, a gas supply line for supplying an arbitrary gas having an oxygen content of 10 vol % or less to the fine-bubble generating device, the fine-bubble generating device for generating a fine-bubble-containing liquid by causing the gas to be contained in the liquid as fine bubbles, a separation container for separating dissolved oxygen from the fine-bubble-containing liquid, and a separated liquid supply line connected to the separation container for supplying the separated liquid from which the dissolved oxygen has been separated to the outside, the fine-bubble generating device comprises a mixer which mixes the gas and the liquid, a mixed fluid supply line which supplies the mixed fluid mixed in the mixer to a plurality of nozzle parts, a booster pump which pressurizes at least either the liquid supplied from the liquid supply line or the mixed fluid mixed in the mixer, and the plurality of nozzle parts which are connected to the mixed fluid supply line and are provided in parallel within the liquid in the separation vessel, and which spray and shear the pressurized mixed fluid to generate fine bubbles, The fine bubbles have a most frequent particle size of 1000 nm or less in a particle size distribution based on the number of bubbles.

2. 2. The dissolved oxygen removal device according to claim 1, wherein the concentration of the microbubbles contained in the microbubble-containing liquid is 150 million bubbles / mL or more.

3. 3. The dissolved oxygen removal device according to claim 1, further comprising a circulation line through which the microbubble-containing liquid in the separation container circulates, the circulation line comprising a circulation pipeline, a circulation pump provided midway through the circulation pipeline, and a throttle section provided in the circulation pipeline.

4. 4. The dissolved oxygen removing device according to claim 1, wherein the liquid is a beverage.

5. 5. The dissolved oxygen removing device according to claim 1, wherein the liquid is boiler water.

6. The method includes a liquid supplying step of supplying a liquid to a micro-bubble generating device, a gas supplying step of supplying an arbitrary gas having an oxygen content of 10 vol % or less to the micro-bubble generating device, a micro-bubble-containing liquid generating step of causing the gas supplied in the gas supplying step to be contained as micro-bubbles in the liquid supplied in the liquid supplying step, and a dissolved oxygen removing step of removing oxygen dissolved in the micro-bubble-containing liquid generated in the micro-bubble-containing liquid generating step, The microbubble generating device is composed of a mixer that mixes the gas and the liquid, a mixed fluid supply line that supplies the mixed fluid mixed in the mixer to a plurality of nozzle parts, a booster pump that pressurizes at least either the liquid supplied from the liquid supply line or the mixed fluid mixed in the mixer, and the plurality of nozzle parts that are connected to the mixed fluid supply line and are provided in parallel within the liquid in the separation container, and spray and shear the pressurized mixed fluid to generate microbubbles, A method for removing dissolved oxygen, wherein the fine bubbles have a most frequent particle size of 1000 nm or less in a particle size distribution based on the number of bubbles.

7. 7. The method for removing dissolved oxygen according to claim 6, wherein the concentration of the microbubbles contained in the microbubble-containing liquid is 150 million / mL or more.

8. 8. The method for removing dissolved oxygen according to claim 6, further comprising a circulation step of circulating the micro-bubble-containing liquid so that the dissolved oxygen concentration in the micro-bubble-containing liquid is equal to or lower than a predetermined concentration in the dissolved oxygen removal step.

9. 9. The method for removing dissolved oxygen according to claim 6, wherein the liquid is a beverage.

10. 10. The method for removing dissolved oxygen according to claim 6, wherein the liquid is boiler water.

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