JP2010269218A - Method of generating gas/liquid mixed solution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of generating a gas/liquid mixed solution in which a gas is present in a liquid in a high density for a long period in the form of stable nano-size bubbles. <P>SOLUTION: A liquid injected with a gas is pressurized at a pressurization rate ΔP<SB>1</SB>/t (ΔP<SB>1</SB>is an increase in pressure; and t is time) of ≥0.17 MPa/s to a pressure of ≥0.15 MPa. Then, the pressure is reduced to the atmospheric pressure at a pressure reduction rate ΔP<SB>2</SB>/t (ΔP<SB>2</SB>is a decrease in pressure; and t is time) of ≤2,000 MPa/s while feeding the liquid. A liquid mixed with nano-size bubbles is thus generated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a gas-liquid mixed solution in which nano-sized bubbles are stably present in a liquid.

  Conventionally, a gas-liquid mixed liquid in which fine bubbles are dispersed in a liquid is known. In particular, nanobubble water in which nano-order size bubbles are mixed with water has extremely small bubble size compared to normal bubbles, and therefore has unique properties, and has been tried to be used in various fields. (For example, refer to Patent Document 1).

  However, the fine bubbles in the liquid tend to disappear by dissolving or coalescing, and it has been difficult to stably exist in the liquid. For this reason, gas is continuously supplied to the liquid for bubbling, or a strong force is applied to agitate to generate bubbles, and the liquid is used so that the generated bubbles do not disappear. Yes. Further, as the size of the bubbles becomes nano-order and the size of the bubbles becomes finer, the bubbles are more difficult to be generated and more easily disappeared, and it is more difficult to use the liquid in which the bubbles are dispersed.

  Patent Documents 2 to 4 disclose that microbubbles are rapidly reduced to stabilize nanobubbles. In the methods of these documents, a part of microbubbles is reduced by applying a force of strength, and both ions having opposite signs attracted to an aqueous solution near the interface by ions adsorbed on the gas-liquid interface and electrostatic attractive force. The ions are concentrated in a minute volume at a high concentration to act as a shell surrounding the microbubbles, and the nanobubbles are stabilized by inhibiting diffusion of the gas in the microbubbles into the aqueous solution. However, in order to stabilize nanobubbles, it is necessary to generate an electrostatic force at the gas-liquid interface, so the presence of an electrolyte is indispensable. In solutions such as pure water in which an electrolytic substance is not dissolved, nanobubbles are prevented. It could not exist stably.

  In addition, since only a part of the microbubbles is reduced, there is a problem that the amount of nanobubbles is small and it is difficult to obtain the effect. Furthermore, since the nanobubbles are stabilized by ions surrounding the bubble, it is not easy to control the stable state of the bubble by dissolving or coalescing the bubble, and the use of a gas-liquid mixture is not possible. It was limited.

  Patent Document 5 discloses that nanobubbles are generated by electrolyzing water and then applying ultrasonic waves. However, in the electrolysis of water, the gas is limited to hydrogen and oxygen, the amount of gas generated by electrolysis is small, and the generated bubbles are not stabilized. And the bubbles could not be stably maintained over a long period of time.

JP 2008-156320 A JP 2005-245817 A JP 2005-246293 A JP 2005-246294 A JP 2003-334548 A

  The present invention has been made in view of the above points, and provides a method for producing a gas-liquid mixture in which a gas exists in a liquid as a high-density and stable nano-sized bubble over a long period of time. It is intended.

In the method for producing a gas-liquid mixture of the present invention, a liquid into which a gas is injected is pressurized at a pressurization rate ΔP ₁ / t (ΔP ₁ : pressure increase, t: time) of 0.17 MPa / sec or more. After the pressure is increased to 0.15 MPa or more, nano-sized bubbles are reduced by reducing the pressure to atmospheric pressure at a reduced pressure rate ΔP ₂ / t (ΔP ₂ : reduced pressure amount, t: time) of 2000 MPa / sec or less while feeding the liquid. To produce a mixed liquid.

  According to this invention, by rapidly pressurizing a liquid into which gas has been injected, bubbles having a strong interface structure are generated, and nano-sized bubbles that exist stably even when the pressure is returned to atmospheric pressure are generated. In addition, by gradually depressurizing the gas-liquid mixture having bubbles with a solid interface structure to atmospheric pressure, the bubbles can be eliminated or combined while maintaining a strong interface structure. In addition, it is possible to stably obtain a gas-liquid mixed liquid in which nano-sized bubbles are mixed, and to efficiently and easily generate the gas-liquid mixed liquid.

  The method for producing a gas-liquid mixed liquid according to claim 2 is characterized in that in the gas-liquid mixed liquid producing method described above, the liquid is pressurized by the pump 11.

  According to the present invention, since the liquid can be rapidly pressurized by pressurizing with the pump, a gas-liquid mixed liquid having a strong bubble interface structure can be reliably generated.

  The method for producing a gas-liquid mixed liquid according to claim 3 is characterized in that, in the above-mentioned gas-liquid mixed liquid producing method, the pump 11 pressurizes the liquid while shearing the liquid using the rotating body 21. It is.

  According to this invention, the gas injected into the liquid can be sheared and formed into nano-sized bubbles by applying a sudden strong force with the rotating body. Can be generated more reliably.

  According to a fourth aspect of the present invention, there is provided a method for producing a gas-liquid mixture, wherein the liquid is pressurized by a venturi tube in the method for producing a gas-liquid mixture.

  According to the present invention, since the liquid can be rapidly pressurized by pressurizing with the venturi tube, a gas-liquid mixed solution having a strong bubble interface structure can be reliably generated.

  The method for producing a gas-liquid mixed liquid according to claim 5 is characterized in that, in the above-mentioned gas-liquid mixed liquid producing method, pressurization is performed a plurality of times while feeding the liquid.

  According to the present invention, by pressurizing a plurality of times while feeding the liquid, the pressurization can be performed by a plurality of pumps or venturi pipes, and the liquid is strongly pressurized and the gas-liquid mixing has a strong structure at the bubble interface. A liquid can be produced.

  According to the present invention, by rapidly pressurizing a liquid into which gas has been injected, bubbles having a strong interface structure are generated, and nano-sized bubbles that exist stably even when the pressure is returned to atmospheric pressure are generated. In addition, by gradually depressurizing the gas-liquid mixture having bubbles with a solid interface structure to atmospheric pressure, the bubbles can be eliminated or combined while maintaining a strong interface structure. In addition, it is possible to stably obtain a gas-liquid mixed liquid in which nano-sized bubbles are mixed, and to efficiently and easily generate the gas-liquid mixed liquid.

(A) It is the schematic which shows an example of embodiment of the production | generation method of a gas-liquid mixed liquid, (b) is the schematic which shows the one part. (A)-(c) is the schematic which respectively shows a part same as the above. (A)-(d) is the schematic which respectively shows a part same as the above. It is the schematic which shows a part same as the above. It is the schematic which shows another example of embodiment of the production | generation method of a gas-liquid liquid mixture. It is a graph which shows the difference of the infrared absorption spectrum of the gas-liquid mixed liquid using nitrogen and water, and nitrogen saturated water. It is a graph which shows the gas volume contained in a gas-liquid liquid mixture. It is a photograph of the gas-liquid mixed solution by a scanning electron microscope (SEM). It is a conceptual explanatory drawing of the gas-liquid interface of the bubble in a gas-liquid mixed liquid. It is a graph which shows stability of a gas-liquid liquid mixture.

  Hereinafter, modes for carrying out the invention will be described.

In the method for producing a gas / liquid mixture of the present invention, a liquid into which gas has been injected is added at a pressure rate ΔP ₁ / t (ΔP ₁ : pressure increase, t: time) of 0.17 MPa / sec or more. Press. At that time, the pressure of the liquid is set to 0.15 MPa or more by pressurization. Thereafter, the pressure is gradually reduced to atmospheric pressure by setting the upper limit of the pressure reduction rate ΔP ₂ / t (ΔP ₂ : pressure reduction amount, t: time) in the entire piping while feeding the liquid. Thereby, a liquid in which nano-sized bubbles are mixed can be generated.

  The bubbles contained in the gas-liquid mixture are nano-sized bubbles, specifically, bubbles of 1000 nm or less (so-called nano bubbles). When the bubbles are nano-sized and fine, a strong bubble interface structure can be formed, and a high-concentration gas can be held in the liquid. Further, since buoyancy does not act on the nano-order size bubbles, the bubbles do not rise and separate from the liquid, so that the bubbles can exist stably over a long period of time. If the bubble size is larger than the nano size, the bubble may not be stabilized. In addition, the bubble size can be measured by a scanning electron microscope (SEM), and the average particle diameter of the bubbles can be obtained by averaging the particle diameters of the bubbles obtained by the measurement. By the way, the liquid mixed with microbubbles is cloudy and can be discriminated visually. However, the liquid mixed with nanobubbles is colorless and transparent (or the color of the liquid when the liquid is colored) and can be discriminated visually. Can not. Therefore, the determination of the gas-liquid mixture is performed by SEM, density measurement, or the like. The lower limit of nano-sized bubbles is 1 nm.

  As the liquid used for the production of the gas-liquid mixture, it is preferable to use a liquid composed of molecules that form hydrogen bonds. A hydrogen bond is a bond that stabilizes the system in a molecule that has a high electronegativity atom and a hydrogen atom, because the hydrogen atom approaches the high electronegativity atom of another molecule. . Bubbles are present in the liquid forming the gas-liquid mixture, and in the liquid molecules existing around the bubbles, that is, at the interface with the bubbles, the distance of hydrogen bonding between the molecules is The distance is shorter than the hydrogen bond distance at (25 ° C., 1 atm (0.1013 MPa)). In this way, when the gas-liquid mixture exists under normal temperature and normal pressure conditions, the hydrogen bond distance at the bubble interface becomes shorter than the normal hydrogen bond distance at normal temperature and normal pressure, thereby It will be surrounded by liquid molecules that form strong hydrogen bonds. And the liquid molecule which formed this hydrogen bond turns into a firm shell, and encloses a bubble. As a result, even if the bubbles collide with each other, they will not collapse, and the pressure from the liquid can be countered by the stress from the inside of the bubbles, so the bubbles can be held without disappearing or coalescing in the liquid. Is something that can be done. In other words, it is different from conventional bubbles that are stable with surface tension. Thus, particularly when a liquid composed of molecules that form hydrogen bonds is used as the liquid, the distance between the hydrogen bonds of the molecules present at the interface with the bubbles of the liquid is determined when the liquid is at normal temperature and pressure. Since the distance can be shorter than the distance between hydrogen bonds, nano-sized bubbles can be more stably present.

  One of the liquids preferably used for the gas-liquid mixture is water. The water molecule is a hydrogen bond of O ... H, that is, a hydrogen bond is formed between an oxygen atom of one water molecule and a hydrogen atom of another water molecule, and water is used as the liquid of the gas-liquid mixture. Then, this hydrogen bond in the liquid becomes stronger at the bubble interface, and the bubbles can be further stabilized. In addition, water can be obtained stably with abundant supply sources, and furthermore, water in which bubbles are dispersed has a wide range of applications, so that a highly useful gas-liquid mixture can be obtained. That is, in the present invention, the water is not limited to high-purity water, and any water can be used including water and sewage systems, ponds, seawater, and the like. That is, any material that contains water as a liquid may be used.

Further, the liquid is a liquid composed of molecules having any one or more of (halogen) -H bond and S—H bond such as O—H bond, N—H bond, F—H bond and Cl—H bond. It is also preferable. These bonds are bonds between atoms and hydrogen atoms having a sufficiently large electronegativity with respect to hydrogen atoms, such as OH ... O, NH ... N, FH ... F, and Cl-H ... Cl. (Halogen) -H (Halogen), S—H,... S, and so on, are formed, and by this hydrogen bond, bubbles can be surrounded and stabilized. A typical liquid having an O—H bond is water, but other examples include hydrogen peroxide, alcohols such as methanol and ethanol, and glycerin. Moreover, ammonia etc. can be illustrated as a liquid which has a N-H bond. Examples of those having a (halogen) -H bond include HF (hydrogen fluoride) having an F-H bond and HCl (hydrogen chloride) having a Cl-H bond. Examples of those having an S—H bond include H ₂ S (hydrogen sulfide).

  It is also preferable that the liquid is a liquid composed of molecules having a carboxyl group. The carboxyl group has a carbonyl oxygen atom with high electronegativity, and the carbonyl oxygen atom in one carboxyl group and a hydrogen atom in another carboxyl group form a strong hydrogen bond to surround the bubble. Therefore, it is possible to obtain a gas-liquid mixture in which bubbles are stably present. Examples of the liquid composed of molecules having a carboxyl group include carboxylic acids such as formic acid and acetic acid.

  The gas used for the gas-liquid mixture is not particularly limited, and various gases can be used. For example, gases such as air, carbon dioxide, nitrogen, oxygen, ozone, argon, hydrogen, helium, methane, propane, and butane can be used singly or in combination.

  The amount of gas injected into the liquid is preferably such an amount that the concentration of the gas contained in the gas-liquid mixed liquid is equal to or higher than the saturated dissolution concentration of the liquid when it is generated. If a saturated gas amount or a large amount of gas exceeding it is held in the liquid, a high-concentration gas contained in the liquid can be used, and the utility value of the gas-liquid mixture can be increased. . More preferably, a saturated dissolved amount of gas is dissolved in the gas-liquid mixed liquid, and bubbles are present in the saturated dissolved liquid. If the gas is dissolved in the saturated dissolution amount, it becomes possible to stabilize the gas in the form of bubbles without dissolving them and to hold them in the liquid as bubbles. In other words, a gas-liquid mixed solution in which a gas is present in excess of the saturated dissolution amount has a gas dissolved at a saturated concentration in the liquid, and the bubbles do not collapse or dissolve, and the bubbles are more stably contained in the liquid. Can be present. Furthermore, it is preferable that the dissolved concentration of the gas is a saturated dissolved concentration. When the gas concentration is increased in this way, the bubbles can be stabilized in a state where the hydrogen bond distance is shortened, and the action of various activities (physiological activity, detergency, etc.) becomes stronger, and the utility value is increased. Can be further increased. The amount of gas in the gas-liquid mixture can be calculated from the amount of mass change by separating the gas from the gas-liquid mixture as shown in the examples described later.

  In the generation of the gas-liquid mixture, it is preferable that the gas pressure forming the bubbles, that is, the internal pressure of the bubbles is 0.12 MPa or more, and the Young Laplace equation (the following equation) It is preferable that the pressure be higher than the internal pressure of the bubbles given by

Young Laplace's formula ΔP = 2σ / r
[ΔP: rising pressure inside the bubble, σ: surface tension, r: bubble radius]

  When the internal pressure of the bubbles becomes such a pressure, the bubbles are maintained at a high internal pressure, and a stronger interface structure can be formed. Therefore, stable bubbles can be formed in a stationary state. On the other hand, once an impact is applied to the gas-liquid mixture, the balance of the internal pressure force is disrupted, the liquid shell in which hydrogen bonds are formed collapses, the bubbles merge, foam and escape from the liquid Therefore, this foaming can be used. The internal pressure of the bubbles in the gas-liquid mixed liquid can be calculated by applying the total gas amount in the gas-liquid mixed liquid and the gas volume calculated from the density to the gas equation of state as shown in the examples described later.

  Further, the hydrogen bond distance of the liquid molecules at the interface with the bubble will be appropriate depending on the liquid used, but it will be 99% or less when the hydrogen bond distance at room temperature and normal pressure is 100%. It is preferable to produce a gas-liquid mixture. When the hydrogen bond distance falls within this range, the bubbles can be surrounded and stabilized by a hard shell of hydrogen bonds. If the distance between hydrogen bonds is longer than this, there is a possibility that bubbles cannot be stabilized and exist. Considering the interatomic distance, the lower limit of the hydrogen bond distance is 95%. The hydrogen bond distance at the bubble interface in the gas-liquid mixture can be calculated by analyzing the infrared absorption spectrum (IR) of the gas-liquid mixture as shown in the examples described later.

  By the way, water having a hydrogen bond distance of the above-mentioned distance usually has a solid or hydrate crystal structure like ice. However, in the gas-liquid mixture produced by the present invention, it is locally present at the bubble interface. In general, hydrogen bonds having a short distance as described above are formed, and normal hydrogen bonds are formed in other liquids. That is, a hard shell of liquid molecules is formed by hydrogen bonds at a short distance at the bubble interface to prevent the bubbles from coalescing and disappearing, and at other than the bubble interface, liquid exists in a normal state and normal temperature At normal pressure, fluidity is ensured, and it is easy to use liquid in which stable bubbles are present.

In addition, when water is used as the liquid, the gas-liquid mixture produced according to the present invention has a negative zeta potential, and the area of the bubble interface existing in a volume of 1 cm ³ is about 1.2 m ² . Such characteristics can be used in various fields.

  FIG. 1 is a schematic diagram showing an example of an embodiment of a method for producing a gas / liquid mixture of the present invention, and an example of an apparatus (gas / liquid mixture production apparatus) for producing a gas / liquid mixture is illustrated. .

  This gas-liquid mixed liquid manufacturing apparatus is an apparatus for continuously manufacturing a gas-liquid mixed liquid by pumping liquid, taking out the liquid held at atmospheric pressure (0.1 MPa) from the liquid storage tank 12 and pumping it. A pressurizing unit 1 that pressurizes the gas, a gas supply unit 2 that supplies a gas to the pressurized liquid, a gas-liquid mixing unit 3 that mixes the supplied gas with fine liquids, and a gas-liquid mixing unit 3 is a defoaming unit 4 that removes large bubbles present in the liquid, and a depressurizing unit that gradually depressurizes the pressure of the liquid from which the large bubbles have been removed by the defoaming unit 4 to the atmospheric pressure without generating large bubbles. 5 and a discharge part 7 for discharging the decompressed liquid, each part being provided connected to the flow path 6.

  The pressurizing unit 1 pumps the liquid to the gas-liquid mixing unit 3 and can be constituted by, for example, a pump 11 that sucks the liquid from the liquid storage tank 12 as in this device. It can also be composed of piping that sends out pressure. The gas supply unit 2 is connected to the flow path 6 to supply and inject a gas to the liquid. For example, when injecting air as a gas, a tube body having one end opened to the atmosphere. The other end can be connected to the flow path 6 to form the gas supply unit 2. Or when supplying oxygen, ozone, hydrogen, nitrogen, a carbon dioxide, argon etc. as gas, the gas supply part 2 can be formed by connecting the cylinder etc. which enclosed these gas to the flow path 6. FIG. The connection position of the gas supply unit 2 to the flow path 6 may be a position upstream of the gas-liquid mixing section 3 and is connected to the flow path 6 upstream of the pressurizing section 1 as in this device. Alternatively, it may be either connected to the flow path 6 on the downstream side of the pressurizing unit 1.

  The gas-liquid mixing unit 3 mixes the liquid fed under pressure and the gas injected into the liquid, and converts the gas into fine bubbles by pressurization and disperses and mixes them in the liquid. The gas-liquid mixing unit 3 can be configured by applying a stirring force by changing the cross-sectional area of the flow path, or if the liquid is flowing in the flow path 6 with the liquid being stirred, 6 can also be configured. When the gas supply unit 2 is in the flow path 6 on the upstream side of the pressurizing unit 1 as in this apparatus, the pressurizing unit 1 constituted by the pump 11 or the like may also be used as the gas-liquid mixing unit 3. When pressurization and mixing of gas and liquid are performed by the pump 11, the liquid can be rapidly pressurized and mixed, so that a gas-liquid mixture having a strong bubble interface structure can be reliably generated. Moreover, it is also preferable that the gas-liquid mixing unit 3 is constituted by a Venturi tube. In that case, the liquid can be rapidly pressurized and mixed with a simple configuration.

  In the gas-liquid mixing unit 3, the liquid and the gas are mixed under high pressure conditions. Thereby, a strong interface structure is formed around the bubble, and the bubble can be covered with the shell of the strong interface structure, and the gas can be stabilized as a fine bubble.

By the pressurization unit 1 and the gas-liquid mixing unit 3 as described above, a strong pressure is suddenly applied to the liquid into which the gas is injected, and the bubbles existing in the liquid are subdivided into fine nano-sized bubbles. And dispersed in the liquid. In addition, a strong interface structure is formed by liquid molecules at the interface of the bubbles that have become high pressure due to a sudden pressure change. At that time, when the pressurization rate ΔP ₁ / t (ΔP ₁ : pressure increase, t: time) is 0.17 MPa / sec or more, the bubbles are subdivided to generate fine nano-sized bubbles. The pressure of the gas-liquid mixed liquid when it is sent out from the gas-liquid mixing part 3 to the defoaming part 4 becomes 0.15 MPa or more, thereby generating nano-sized bubbles with a strong structure at the bubble interface Is something that can be done. In consideration of substantial pressurization conditions, the upper limit of the pressurization rate ΔP ₁ / t is 167 MPa / sec, and the upper limit of the pressure of the pressurized gas-liquid mixture is 50 MPa.

  FIG. 1B is a schematic diagram of a main part showing an example of a specific form of the pump 11. The pump 11 a pressurizes the liquid by the rotation of the rotating body 21, and the rotating blades 22 attached to the rotating body 21 continuously rotate to pump the pump outlet 27 through the pump passage chamber 23 from the pump inlet 26. The liquid is sent out in the direction of flow to and pressurized. In the figure, the white arrow indicates the flow direction of the liquid, and the solid line arrow indicates the rotation direction of the rotating body 21. The pump 11a includes four rotary blades 22. Further, the rotating shaft 25 of the rotating body 21 is arranged so as to be deviated toward the pump outlet 27 side from the cylindrical center of the pump wall 24 formed in a cylindrical shape, and is provided as an eccentric shaft. The volume of the second flow path chamber 23b of the pump flow path chamber 23 is formed smaller than the volume of the first flow path chamber 23a due to the eccentricity of the rotary shaft 21, and the pump flow path chamber is arranged along the liquid flow direction. The volume of 23 is gradually reduced.

Then, the liquid fed to the pump flow passage chamber 23 is pressurized is fed by rotating blades 22, large bubbles B _B due to rapid pressure changes bubbles B _N of subdivided by fine nano-sized generated . That is, the liquid sent from the first flow path chamber 23a to the second flow path chamber 23b along with the rotation of the rotating body 21 is rapidly compressed and pressurized as the volume of the pump flow path chamber 23 becomes smaller. Nano-sized bubbles _BN are generated by the pressure. Further, in the illustrated pump 11a, a shearing force is applied when the liquid passes between the inner surface of the pump wall 24 and the tip of the rotor blade 22, and the liquid is pressurized while being sheared by the clearance. At this time, the gas (large bubbles B _B ) mixed in the liquid is sheared by the shearing force applied to the liquid and becomes finer nano-sized bubbles (B _N ). The distance narrowest part between the inner surface of the pump wall 24 and the tip portion of the rotor blades 22, i.e. the clearance distance L _C is preferably 5Myuemu～2mm. Thus, according to the pump 11a using the rotator 21, it is possible to form nano-sized bubbles by shearing the gas injected into the liquid while being rapidly pressurized with the rotator 21 with a strong force. A gas-liquid mixture having a strong bubble interface structure can be generated more reliably.

  The rotational speed of the rotating body 21 of the pump 11 is preferably 100 rpm or more. At this time, it becomes 1/2 rotation or more in 0.3 seconds. By having such a rotational speed, it is possible to reliably generate nano-sized bubbles in which the hydrogen bond distance is shortened by injecting a gas having a saturation dissolution concentration or more into the liquid.

  The pressurization by the pressurizing unit 1 and the gas-liquid mixing unit 3 can be performed multiple times by providing a plurality of pressurizing units 1 or gas-liquid mixing units 3. By pressurizing the liquid a plurality of times while feeding the liquid, the pressurization can be performed by a plurality of pumps 11 and venturi pipes, and the liquid is strongly pressurized to generate a gas-liquid mixture having a strong bubble interface structure. It is something that can be done. Specifically, the pressurizing unit 1 can be configured with a pump 11 as shown in FIG. 1, and the gas-liquid mixing unit 3 can be configured with one or more pumps 11 or Venturi tubes.

  The defoaming section 4 is for removing bubbles exceeding nanosize, that is, bubbles exceeding 1 μm in diameter, from the liquid in which the gas is mixed as described above. The bubbles are lifted by their own buoyancy and removed. It can be composed of a tube or the like. Since the removed bubbles become gas and accumulate on the upper part, the removed gas can be removed by the gas removing unit 8. Bubbles of a size exceeding 1 μm in diameter (micro-sized bubbles) are raised by buoyancy, so that relatively large bubbles are removed and nano-sized bubbles that are fine bubbles are present in the liquid. It is possible to obtain a stable gas-liquid mixture having a strong interface structure.

  Specifically, the defoaming portion 4 can be configured as shown in FIG. (A) is formed so as to be substantially horizontal to the ground surface (on a plane substantially perpendicular to the direction of gravity) continuously with the gas-liquid mixing unit 3, and the bubbles B in the liquid Lq are It shows an example of a tubular body that is lifted up to remove bubbles B. (B) is formed so that the shape combined with the gas-liquid mixing unit 3 and the gas-liquid mixing unit 3 is a reverse L-shape when viewed from the front, and the flow direction of the liquid Lq is downward (the direction of gravity) In this example, the bubbles B are removed by raising the bubbles B in the liquid Lq to the liquid level by the buoyancy. Further, (c) is separated from the gas-liquid mixing unit 3, and the flow direction of the liquid Lq is set downward (substantially the same direction as the direction of gravity), and the bubbles B in the liquid Lq are raised to the liquid level by the buoyancy. This shows an example of a tubular body that is made to remove bubbles B.

The decompression unit 5 gradually reduces the pressure of the liquid mixed with gas to atmospheric pressure without generating large bubbles. When the liquid mixed with gas by pressurization as described above is in a high-pressure state and is discharged to the outside under atmospheric pressure as it is, bubbles in the gas-liquid mixture are combined due to a sudden pressure drop. May become a gas and be discharged from the liquid, and cavitation may occur. Therefore, the decompression unit 5 is provided, and when the gas-liquid mixture in a pressurized state is sent out, the decompression unit 5 gradually reduces the pressure to atmospheric pressure and then discharges it. The decompression unit 5 is configured to decompress while reducing the upper limit of the decompression speed ΔP ₂ / t (ΔP ₂ : decompression amount, t: time) over the entire piping while sending a liquid in which gas is mixed. ing. Thus, the gas-liquid mixture can be taken out without erasing or coalescing the nano-sized bubbles while maintaining the structure of the strong bubble interface.

The decompression unit 5 can be configured as shown in FIG. 3, and specifically, the flow path 6 in which the cross-sectional area of the flow path gradually decreases as shown in FIG. In this way, the flow path 6 in which the cross-sectional area of the flow path gradually decreases gradually, or the gas-liquid mixing in the high pressure state (P ₁ ) due to the pressure loss in which the pressurized liquid flows in the flow path 6 as in (c) The flow path 6 whose flow path length (L) is adjusted so as to reduce the pressure of the liquid gradually (P ₂ , P ₃ ,...) To the atmospheric pressure (P _n ), and (d) Thus, it can be configured by a plurality of pressure regulating valves 9 provided in the flow path 6.

For example, when the decompression unit 5 as shown in FIG. 3A or 3B is used, the flow path 6 upstream of the decompression unit 5 has an inner diameter of 20 mm, and the decompression unit 5 has a flow path length of about 1 cm to At 10 m, the inner diameter can be gradually reduced from 20 mm to 4 mm so that the cross-sectional area of the flow path can be reduced. In addition, the decompression part 5 can be set to inlet inner diameter / outlet inner diameter = about 2-10, or the inner diameter reduction | decrease value per cm can be set to about 1-20 mm. At this time, if the gas-liquid mixed solution is sent to the decompression unit 5 at a flow rate of 4 × 10 ⁻⁶ m / s or more, the decompression rate is 2000 MPa / sec or less and the pressure can be reduced by 1.0 MPa without erasing the nano-sized bubbles. The gas-liquid mixture can be depressurized to atmospheric pressure.

  The discharge part 7 discharges the decompressed liquid. As shown in FIG. 4, an extension flow path 10 may be provided between the discharge unit 7 and the decompression unit 5 in order to ensure a sufficient pressure of the liquid in the pressurization unit 1. That is, the total pressure loss including the decompression unit 5 is calculated, the pressure required to pressurize the liquid and gas in the gas-liquid mixing unit 3 by the indentation pressure from the pressurization unit 1, and the total pressure loss The extended flow path 10 may be added to the flow path 6 with the flow path length adjusted so that the pressure loss of this difference occurs. In order to secure the indentation pressure, it may be possible to provide a throttling portion or the like. However, if the indentation pressure is adjusted by the throttling portion or the like, bubbles may collapse due to a sudden pressure change. However, if the extension channel 10 is provided in this way, the gas-liquid mixture can be discharged while the bubbles are stabilized.

In the gas-liquid mixed liquid manufacturing apparatus configured as described above, the liquid is pumped by the pressurizing unit 1, and the gas is supplied and injected into the liquid pumped by the gas supply unit 2. Then, the liquid into which the gas has been injected is pressurized by the pressurizing unit 1 and the gas-liquid mixing unit 3 at a pressurization rate ΔP ₁ / t (ΔP ₁ : pressure increase, t: time) of 0.17 MPa / sec or more. The liquid pressure is set to 0.15 MPa or more. That is, the pressure of the liquid when being sent out from the gas-liquid mixing unit 3 to the defoaming unit 4 is 0.15 MPa or more. Thereafter, after the bubbles exceeding the nano size in the gas-liquid mixed solution are removed by the defoaming part 4, the pressure reduction rate ΔP of the maximum pressure reduction rate of 2000 MPa / sec or less while sending the liquid to the pressure reduction part 5 and the flow path 6 on the downstream side. _The pressure is gradually reduced to atmospheric pressure at ₂ / t (ΔP ₂ : reduced pressure amount, t: time). As a result, a gas-liquid mixed liquid in which nano-sized bubbles are stably present can be generated.

  The flow path 6 on the downstream side of the gas-liquid mixing unit 3 can be formed in a tube having an inner diameter of about 2 to 50 mm. As a result, the gas-liquid mixture can be discharged with a relatively thick channel cross-sectional area, and the clogging of the pipe as in the case where the channel 6 is configured by a narrow path can be prevented, and the gas-liquid mixture can be used. It can be made easier.

FIG. 5 is another example of an embodiment for generating a gas-liquid mixed liquid, and a schematic diagram illustrating another example of the gas-liquid mixed liquid manufacturing apparatus is illustrated. This gas-liquid mixture manufacturing apparatus is configured as a gas-liquid mixing tank 13 in which the pressurizing unit 1 and the gas-liquid mixing unit 3 are combined, and the liquid into which gas is injected in the gas-liquid mixing tank 13 By pressurizing at a pressurization rate ΔP ₁ / t (ΔP ₁ : pressure increase, t: time) of 0.17 MPa / sec or more, and setting the liquid pressure to 0.15 MPa or more, bubbles with a strong interfacial structure A gas-liquid mixed solution is produced in a batch system, and after removing large bubbles from the gas-liquid mixed solution by the defoaming unit 4, the gas-liquid mixed solution is sent to the decompression unit 5 and the pressure is reduced to a maximum decompression speed of 2000 MPa / sec. The pressure is reduced to atmospheric pressure at the following pressure reduction rate ΔP ₂ / t (ΔP ₂ : pressure reduction amount, t: time), and the gas-liquid mixture is discharged from the discharge part 7. The gas-liquid mixing tank 13 which is a closed system is sent out and pressurized in a batch manner, and is stirred by a stirring blade 14 or the like provided in the gas-liquid mixing tank 13 so that the liquid Lq and the gas are mixed. Are mixed under high pressure conditions. Thereby, the interface structure around the bubbles can be strengthened, and the gas can be stabilized as nano-sized bubbles. Then, by sending the generated gas-liquid mixed liquid to the defoaming section 4, the decompression section 5 and the discharge section 7 configured in the same manner as the apparatus of FIG. 1, the gas-liquid mixed liquid in which nano-sized bubbles are mixed is obtained. It can be obtained.

  The gas-liquid mixed liquid produced by the present invention holds a gas such as carbon dioxide, nitrogen, oxygen, ozone, or argon as a fine bubble in the liquid, and these gases are stably contained in the liquid at a high concentration. Therefore, it can be used in the environmental field, the manufacturing / industrial field, the energy field, the agriculture / forestry / fishery field, the food field, the household field, the medical field, and other various fields.

  For example, in the environmental field, the oxygen abundance in the water area is increased by supplying a gas-liquid mixture in which oxygen is bubbled and present in high concentrations in closed water areas such as the sea, rivers, lakes, ponds, and dam lakes. Water purification can be performed, and similarly, it can be used for oxygen supply in septic tanks, sewerage facilities, and human waste processing facilities. Moreover, harmful substances and oil contamination can be treated by supplying oxygen to the soil.

  In the manufacturing / industrial field, it can be used for cleaning precision parts and the like by jetting or dipping a gas-liquid mixture in which oxygen bubbles are present at a high concentration. In addition, by supplying a gas-liquid mixture in which oxygen bubbles are present at a high concentration to a factory wastewater treatment facility, wastewater treatment can be performed by improving the amount of oxygen, or ozone bubbles are present at a high concentration. By supplying the gas-liquid mixture, the waste water can be subjected to ozone treatment. Moreover, it can utilize for oxygen supply for fermentation and culture | cultivation promotion of fermented food in a food factory. It can also be used to supply oxygen and ozone to circulating water filtration systems such as commercial baths, pools, and aquariums. Oxygen and ozone for factory painting process circulating water, factory cleaning process circulating water, and cooling circulating water It can be used for purification by supply. Furthermore, a gas-liquid mixture is generated by mixing toxic gas generated in factories with water as bubbles, and the toxic gas is processed by processing the gas-liquid mixture in which this high-concentration toxic gas exists. You can also.

  In the energy field, natural gas, hydrocarbons such as methane, butane, ethane, propane, etc., oxygen, nitrogen, hydrogen, ozone, etc. are present in the liquid as bubbles, so that these gases are stably maintained at a high concentration. be able to. And, by cooling or compressing such a gas-liquid mixture, it is solidified or slurried to produce a gas hydrate, and by this gas hydrate, transportation of gas, storage and transportation of fresh food products, It can be used for plant cultivation, carbonated drinks, and fuel.

  In the agriculture, forestry and fisheries field, by supplying a gas-liquid mixture with high concentration of oxygen bubbles to agricultural, fishery and livestock wastewater, the oxygen content is improved and used for water purification and flotation separation of filth. be able to. In addition, by using a gas-liquid mixed solution in which oxygen bubbles are present at a high concentration as agricultural water or fishery water, it is possible to promote the germination and growth of plants and the growth of seafood. Furthermore, by supplying a gas-liquid mixed liquid in which oxygen bubbles are present at a high concentration in the ginger, oxygen can be supplied during transport of live fish. It can also be used for agricultural wastewater treatment.

  In the food field, gas-liquid mixtures containing bubbles such as oxygen and carbon dioxide can be used as food processing water and food washing water, and there are bubbles of inert gases such as nitrogen, helium, and argon. It can be used to prevent food spoilage using a gas-liquid mixture.

  In the household field, by supplying a gas-liquid mixed liquid in which oxygen bubbles are present at a high concentration to a domestic wastewater septic tank or the like, wastewater treatment by improving the amount of oxygen can be performed efficiently. Moreover, a carbon dioxide bath can be formed by supplying a gas-liquid mixed liquid in which bubbles of carbon dioxide exist at a high concentration to the bathtub. Moreover, a gas-liquid liquid mixture can be utilized for drinks and cosmetics.

  In the medical field, use gas-liquid mixtures with high concentrations of oxygen bubbles and gas-liquid mixtures with high concentrations of carbon dioxide bubbles for beverages, cancer treatment, stone destruction, etc. Can do.

  In other fields, a gas-liquid mixed solution can be used as oxygen water for beverages and carbonated water for beverages. Furthermore, a gas-liquid mixture can be used as ozone water used in various fields such as sterilization, decolorization, deodorization, and organic matter decomposition.

  Hereinafter, the present invention will be described with reference to examples.

  Using the apparatus shown in FIG. 1, pure water was used as the liquid, and various gases described later were used as the gas to produce a gas-liquid mixture.

  As the gas-liquid mixing apparatus, an apparatus in which the pressurizing unit 1 and the gas-liquid mixing unit 3 are combined with a pump 11 was used. As the pump 11, a pump 11 a as shown in FIG.

The ratio of gas to liquid (the amount of gas injected into the liquid) was set to 1: 1 as a volume ratio (volume ratio). Moreover, the rotation speed of the rotary body 21 of the pump 11 was set to 1700 rpm. Under this condition, gas is injected into water at atmospheric pressure (0.1 MPa) and then pressurized at a pressure rate ΔP ₁ /t=28.3 MPa / sec. The pressure of the gas-liquid mixture at the time of delivery became 0.6 MPa. Under such conditions, it is considered that the gas is injected into the liquid exceeding the saturated dissolution concentration, the hydrogen bond distance is shortened, and a strong bubble interface structure is formed. This condition (pressurizing condition) is considered to be the best condition at present.

  In addition, the flow path 6 on the upstream side of the decompression unit 5 has an inner diameter of 20 mm. As the decompression unit 5, as shown in FIG. 3 (a), one having an inner diameter that gradually decreases in three stages is used. Specifically, the inner diameter is 14 mm, 8 mm, 4 mm, and each length is about 3.3 mm (decompression). The total length of the part 5 was approximately 1 cm) and was composed of three flow path pipe parts. In addition, a hose having an inner diameter of 4 mm (outer diameter of 6 mm) is used as the flow path 6 and the extension flow path 10 on the downstream side of the decompression unit 5, and the combined length of the downstream flow path 6 and the extension flow path 10 is as follows. It was set to be 2 m. Under these conditions, the decompression unit 5 decompresses the gas-liquid mixture at a maximum decompression speed of 60 MPa / sec and a time of 0.0025 seconds, and further, 1 MPa / sec, time in the downstream channel 6 and the extension channel 10. The gas-liquid mixed liquid was depressurized in 0.5 seconds, and a gas-liquid mixed liquid reduced in pressure to atmospheric pressure (0.1 MPa) was obtained from the discharge part 7 which is the tip of the hose. Note that, under such conditions, a gas-liquid mixed liquid in which gas is injected into the liquid exceeding the saturated dissolution concentration and the hydrogen bond distance is shortened and the structure of the bubble interface is strengthened can be stably generated. It is considered a thing. This condition (decompression condition) is considered to be the best condition at the present time.

[Physical properties of gas-liquid mixture]
Next, the physical properties of the gas-liquid mixture obtained by the present invention will be described.

[Hydrogen bond distance]
FIG. 6 shows an infrared absorption spectrum of a gas-liquid mixed liquid (nitrogen mixed water) using nitrogen as a gas and pure water as a liquid, and nitrogen saturated water in which nitrogen is dissolved in pure water at a saturated dissolution concentration. It is a graph which shows a difference. It is known that an infrared absorption band due to OH contraction vibration of water usually has an absorption maximum in the vicinity of 3400 cm ⁻¹ , but as shown in the graph, the gas-liquid mixture of the present invention has an absorption maximum of OH contraction vibration. Is shifted to around 3200 cm ⁻¹ . When the absorption maximum is 3400 cm ⁻¹ , the hydrogen bond distance is 0.285 nm. On the other hand, when the absorption maximum is 3200 cm ⁻¹ , the hydrogen bond distance is known to be 0.277 nm, which is shorter than the normal hydrogen bond distance under normal temperature and pressure, and is structured ice or hide. It was concluded that the water was close to the rate.

[Gas volume]
The amount of gas present as bubbles in a gas-liquid mixture using pure water as a liquid and nitrogen, hydrogen, methane, argon, or carbon dioxide as a gas was measured by the following method.
(1) Various gases were mixed with pure water having a conductivity of 0.1 μS / cm at 25 ° C. to obtain a gas-liquid mixture.
(2) In order to separate large bubbles having a diameter of 1 μm or more from water, the gas-liquid mixture was allowed to stand at 25 ° C. for 1 day. As for the standing time, from the Stokes' law, the bubble rising speed: V = d ² × g / (18 × γ)
(D: bubble diameter, g: gravitational acceleration, γ: kinematic viscosity coefficient)
From this equation, the rate of rise of bubbles of 1 μm is about 2.4 × 10 ⁻⁴ m / s. For example, if the water depth of the container at the time of standing is 50 mm, Bubbles can be removed.
(3) The mass of the gas-liquid mixture was measured with an analytical balance having a minimum measured value of 1 mg.
(4) A gas-liquid mixture and a stirrer of a stirrer are placed in a PE + nylon resin vinyl bag with low gas permeability and moisture permeability, and the vinyl bag is sealed with a sealer in a state where there is no air in the bag. .
(5) Immediately after sealing, the mass of the vinyl bag in which the gas-liquid mixture was sealed was measured with an analytical balance.
(6) The vinyl bag in which the gas / liquid mixture at 25 ° C. was sealed by a hot stirrer was heated to 45 ° C., and the gas / liquid mixture was stirred for about 5 hours. By this temperature rise and stirring, fine bubbles and gas dissolved at a saturated dissolution concentration of 45 ° C. or higher were separated from the gas-liquid mixture and collected on the top of the vinyl bag.
(7) The set temperature of the hot stirrer was set to 25 ° C. at room temperature of 25 ° C., and the mixture was stirred for several hours so as to become a liquid having a saturation solubility of 25 ° C.
(8) Using an analytical balance, the mass of the vinyl bag in which gas and liquid were enclosed was measured.
(9) The mass of the gas-liquid mixture and the amount of change in the mass of the liquid caused by the buoyancy caused by the gas separated from the gas-liquid mixture by heating and stirring were obtained from three mass measurements. The mass change amount is the same as the mass of air having the same volume as the gas volume separated from the gas-liquid mixture, and the volume and mass of the separated gas can be calculated from this value.

  FIG. 7 is a graph showing the gas volume measured in this way. The lower region of each bar graph is the amount of gas that was present as the measured bubble, and the upper region is the saturated amount of gas that follows Henry's law. As shown in the graph, for example, in the case of a gas-liquid mixture using hydrogen and water, 17.6 mL of hydrogen is dissolved in 1 L of pure water at 25 ° C. as a saturated dissolution amount, and 528 mL of gas exists as fine bubbles. It was confirmed. That is, the amount of gas contained in the gas-liquid mixture was 30 times the amount of supersaturated dissolution. Similarly, the amount of gas contained in the gas-liquid mixture with respect to the amount of supersaturated dissolution was 36 times for nitrogen, 17 times for methane, 16 times for argon, and 1.9 times for carbon dioxide. As described above, the gas-liquid mixed liquid can hold the gas in the liquid at a high concentration equal to or higher than the saturated dissolution concentration, and the high-concentration gas-liquid mixed liquid can be used in various fields. is there.

[Bubble size]
A gas-liquid mixture produced in the same manner as above was instantly frozen, cleaved with a cutter in a vacuum, and methane / ethylene flowed through the fractured surface to discharge, producing a hydrocarbon film (replica film) with transferred irregularities. . A conductive osmium thin film was applied to the replica film, dried sufficiently, and observed with a scanning electron microscope (SEM). FIG. 8 is an example of a photograph observed by SEM for a gas-liquid mixture of nitrogen and pure water. Similarly, by observing photographs, it was confirmed that when nitrogen, hydrogen, methane, argon, carbon dioxide was used as the gas, the bubble size of the gas-liquid mixture was 100 nm in diameter distribution peak. The bubbles in the gas-liquid mixture of the above gas and pure water could not be accurately detected by a particle size distribution measuring apparatus such as a dynamic scattering method using a laser.

[Internal pressure of bubbles]
The pressure inside the bubbles was calculated from the total amount of gas in the gas-liquid mixture. Table 1 shows the total amount of gas and the internal pressure of bubbles calculated from the total amount of gas in a gas-liquid mixed solution of nitrogen, methane, or argon and 25 ° C. pure water.

The internal pressure of the gas in the bubbles is calculated by the following method.
The equation of state of gas is
PV / T = (const)
(P: internal pressure, V: volume, T: internal temperature)
When T is constant, PV = (const)
It is represented by

And the volume of bubbles in the gas-liquid mixture can be calculated from the density of the gas-liquid mixture,
The relationship of atmospheric pressure × total gas volume = bubble internal pressure × total gas volume in liquid is established, and the internal gas pressure in the bubbles is calculated by applying the above measured gas amount to this relational expression. The pressure value is as follows.

For example, if the gas is nitrogen,
Assuming that the volume of water in 1 liter of gas-liquid mixture is w1 liter and the volume of gas in water is w2 liter,
The following relational expression holds for the volume.

  w1 + w2 = 1 liter (Formula A)

  In addition, the following relational expression holds for the mass.

w1 × density of water + w2 ÷ 22.4 (liter) × 28 (molecular weight) = measured mass (Formula B)
Water density: 997.1g / L for pure water at normal temperature and pressure
22.4 liters: volume of 1 mol of gas Measurement mass: 988.3

Solving the above two equations (Equations A and B),
Since w2 = 8.84 × 10 ^ (-3) is calculated,

Internal pressure of gas = atmospheric pressure x total volume of gas ÷ total volume of gas in liquid
= 0.1 x (value in Table 1) / w2
= 0.1 × 0.56 ÷ (8.84 × 10 ^ (-3))
= 6.3 MPa
It becomes.

  In the above calculation, it was assumed that the internal temperature of the bubble was constant (normal temperature), but the actual internal temperature of the bubble is also expected to be higher than the atmospheric temperature (normal temperature). It can be predicted from the gas state equation that the pressure is higher than the above calculation result.

  By the way, in general, the internal pressure of bubbles is calculated as follows. The bubbles are pressurized by the interfacial tension between the gas-liquid interface, and this interfacial tension is derived by Young Laplace's equation (the following equation).

ΔP = 2σ / r
(ΔP: rising pressure, σ: surface tension, r: bubble radius)
According to this equation, for example, in the case of a bubble having a diameter of 100 nm, the bubble internal pressure is 3 MPa.

  On the other hand, the internal pressure in the gas-liquid mixed liquid is 6.3 MPa in the case of nitrogen, for example, as shown in Table 1. In this gas-liquid mixed liquid, bubbles having a diameter of 100 nm are dispersed as shown in the SEM photograph. Therefore, it was confirmed that the bubbles of the gas-liquid mixture had an internal pressure that was about twice or more the value calculated from the Young Laplace equation. Therefore, it was concluded that a stronger interface structure was formed at the bubble interface.

  FIG. 9 is a conceptual explanatory diagram illustrating the mechanism by which the gas-liquid mixture is stabilized. As shown in the drawing, a protective film M having a boundary film structure (crystal structure) is formed at the interface between the bubble B and the liquid Lq by bonding of strong water molecules such as ice or hydrate whose hydrogen bond distance is shorter than usual. Therefore, it is considered that the mass transfer between the gas and liquid was prevented, and the bubbles became stable. The internal pressure of bubbles (nanobubbles) in the gas-liquid mixture of nitrogen, methane, and argon is about twice or more than the pressure obtained from the Young Laplace equation. As described above, the hydrogen bonding distance at the bubble interface is short and the internal pressure of the bubble is increased, so that the bubble becomes a stable gas-liquid mixture.

[Bubble distribution]
The amount of bubble distribution (number) was calculated from Table 1.

When the gas is nitrogen, the total amount of bubbles returned to the atmosphere (0.1 MPa) is 0.56 L, and the internal pressure of the bubbles is 6.3 MPa. Therefore, the total volume V1 of bubbles in water is assumed to change isothermally, PV From = const
V1 = 0.56 × 0.1 ÷ 6.3
It becomes.

Since the bubbles are spheres with a radius r = 50 nm, the volume V2 per bubble is
V2 = 4/3 × π × r ^ 3
It becomes.

  From the above, the number of bubbles per liter of water n = V1 ÷ V2 = 1.7 × 10 ^ 16 is calculated.

  Similarly, the number of bubbles per liter of water is calculated as 1.8 x 10 ^ 16 when the gas is methane and 1.7 x 10 ^ 16 when argon is used.

[Stability of gas-liquid mixture]
FIG. 10 shows the ratio of gas abundance in the gas-liquid mixture with respect to the saturated dissolution concentration when the gas-liquid mixture produced by mixing air with pure water is sealed in a glass bottle and stored at a constant temperature as the degree of supersaturation. It is a graph to display. From the graph, it can be seen that the supersaturation level is 6 even after 400 hours and has hardly changed. Therefore, it was confirmed that the gas-liquid mixture was stable.

DESCRIPTION OF SYMBOLS 1 Pressurization part 2 Gas supply part 3 Gas-liquid mixing part 4 Deaeration part 5 Depressurization part 6 Channel 7 Discharge part 8 Gas removal part 11 Pump 21 Rotating body

Claims (5)

The liquid into which the gas has been injected is pressurized at a pressure rate ΔP ₁ / t (ΔP ₁ : pressure increase, t: time) of 0.17 MPa / sec or higher to bring the pressure to 0.15 MPa or higher, and then the liquid It is characterized in that a liquid in which nano-sized bubbles are mixed is generated by reducing pressure to atmospheric pressure at a pressure reduction rate ΔP ₂ / t (ΔP ₂ : pressure reduction amount, t: time) of 2000 MPa / sec or less. A method for producing a gas-liquid mixture.   The method of producing a gas-liquid mixture according to claim 1, wherein the liquid is pressurized by a pump.   The method for producing a gas-liquid mixture according to claim 2, wherein the pump pressurizes the liquid while shearing it using a rotating body.   The method for producing a gas-liquid mixture according to claim 1, wherein the liquid is pressurized by a Venturi tube.   The method of producing a gas-liquid mixture according to any one of claims 1 to 4, wherein the liquid is pressurized a plurality of times while being fed.