Spray device and spray method

Abstract

Provided are a spray device and a spray method for efficiently forming a fine mist of a stock solution by using a simple method. This spray device includes: a pressure-resistant container; and a spray unit connected to the pressure-resistant container. The pressure-resistant container contains a liquid mixture obtained by mixing a stock solution and liquid carbon dioxide. A mist of the liquid mixture is sprayed from the spray unit, and the temperature of the pressure-resistant container ranges from greater than the triple point temperature of carbon dioxide to less than the critical temperature thereof.

Description

Spraying Device and Spraying Method

[0001] The present invention relates to a spraying device and a spraying method. This application claims priority based on Japanese Patent Application No. 2024-158579 filed in Japan on September 12, 2024, and incorporates its content herein.

[0002] Spraying devices are used in products in a wide range of fields such as hair care styling agents, skin care agents, cooling agents, fragrances, cleaning agents, various coating agents, agricultural chemicals, lubricating oils for mechanical cutting, etc. Conventional spraying devices use compressed gas to pressurize the stock solution and spray it in a fine mist. Examples of compressed gases include air, nitrogen, carbon dioxide gas, nitrous oxide, LP gas, etc. As the stock solution, a wide variety of substances are used depending on the field of use and the purpose of use. For example, there are cases where a stock solution containing a skin care agent composition or a cooling agent composition is sprayed onto the human body (for example, Patent Document 1), and there are also cases where lubricating oil is sprayed onto the workpiece in the cutting process of a metal material (for example, Patent Document 2).

[0003] On the other hand, a spraying method and a spraying device for injecting a mixture of a coating composition and supercritical carbon dioxide fluid using supercritical carbon dioxide fluid have been disclosed (for example, Patent Document 3).

[0004] Japanese Unexamined Patent Application Publication No. 2021-24786, Japanese Unexamined Patent Application Publication No. 02-221796, Japanese Patent Publication No. 03-504689

[0005] Spraying devices using compressed gas as in Patent Document 1 and Patent Document 2 above have room for improvement in the formation of a fine mist. Also, when using compressed air, compressed nitrogen, or compressed carbon dioxide gas, there are problems in handling high-pressure gases, and when using LP gas as a flammable gas, there are problems in safety. Spraying devices using supercritical carbon dioxide fluid as in Patent Document 3 have a problem that the device becomes complicated and expensive because a high-pressure container exceeding the critical pressure of carbon dioxide is used.

[0006] The present invention has been made in view of the above problems, and aims to provide a spraying apparatus and spraying method that can efficiently atomize a stock solution, which is maintained in a liquid state of carbon dioxide and is well mixed (e.g., dissolved or dispersed) with liquid carbon dioxide within a specified temperature and pressure range, into a fine mist using a simple method.

[0007] To solve the above problems, the present invention provides the following means.

[0008] [1] A spraying device comprising a pressure vessel and a spray unit connected to the pressure vessel, wherein the pressure vessel contains a mixed liquid obtained by mixing a stock solution and liquid carbon dioxide, the spray unit sprays the mixed liquid in mist form, and the temperature range of the pressure vessel is above the triple point temperature of carbon dioxide and below the critical temperature. [2] The spraying device according to [1], wherein the carbon dioxide in the pressure vessel is in a subcritical or high-pressure liquid state. [3] The spraying device according to [1] or [2], wherein the pressure range of the pressure vessel is 0.1 MPa or more and 50 MPa or less, and the temperature range of the pressure vessel is -57°C or more and 31°C or less. [4] The spraying device according to any one of [1] to [3], wherein the maximum operating pressure of the pressure vessel is 2 MPa or more and below the critical pressure of carbon dioxide. [5] The spraying device according to any one of [1] to [4], wherein the pressure range of the pressure vessel is above the triple point pressure of carbon dioxide and below the critical pressure. [6] The spraying device according to any one of [1] to [5], wherein the pressure vessel further contains carbon dioxide gas, and the carbon dioxide gas and the liquid carbon dioxide are in gas-liquid equilibrium. [7] The spraying device according to any one of [1] to [6], wherein the injection unit and the pressure vessel are directly connected, and the mixed liquid is supplied from the pressure vessel to the injection unit. [8] The spraying device according to any one of [1] to [7], wherein there is further piping between the injection unit and the pressure vessel, and the mixed liquid is supplied from the pressure vessel to the injection unit through the piping. [9] The spraying device according to any one of [1] to [8], wherein the pressure vessel has a mixed liquid outlet for introducing the mixed liquid to the injection unit and a liquid carbon dioxide supply port for supplying the liquid carbon dioxide to the pressure vessel, and liquid carbon dioxide is supplied to the pressure vessel through the liquid carbon dioxide supply port.

[10] The spraying device according to any one of [1] to [9], wherein the pressure vessel has a mixed liquid outlet for introducing the mixed liquid into the spraying section, a liquid carbon dioxide supply port for supplying the liquid carbon dioxide, and a concentrate supply port for supplying the concentrate, and the liquid carbon dioxide is supplied to the pressure vessel through the liquid carbon dioxide supply port, and the concentrate is supplied to the pressure vessel through the concentrate supply port.

[11] The spraying apparatus according to any one of [1] to

[10] , wherein in the mixture, the stock solution is dissolved or dispersed in the liquid carbon dioxide.

[12] The spraying apparatus according to any one of [1] to

[11] , wherein the stock solution is at least one selected from the group consisting of lemon oil, essential oil components, algal oil, paint, etc.

[13] The spraying apparatus according to any one of [1] to

[12] , wherein in the pressure vessel, the mass ratio of the stock solution to the liquid carbon dioxide (stock solution / liquid carbon dioxide) is 0.01 to 0.99.

[14] The spraying apparatus according to any one of [1] to

[13] , wherein the droplet size of the mist of the stock solution sprayed from the spraying part is 0.1 nm or more and 0.5 μm.

[15] A spraying method comprising a mixing step of mixing the stock solution and liquid carbon dioxide inside a pressure vessel, and a spraying step of spraying the mixture obtained in the mixing step in a mist, wherein the temperature range of the mixture is greater than the triple point temperature of carbon dioxide and less than the critical temperature.

[16] The spraying method according to

[15] , wherein the liquid carbon dioxide is in a subcritical state or a high-pressure liquid.

[17] The spraying method according to

[15] or

[16] , wherein the pressure range of the mixed liquid is 0.1 MPa or more and 50 MPa or less, and the temperature range of the pressure vessel is -57°C or more and 31°C or less.

[18] The spraying method according to any one of

[15] to

[17] , further comprising a liquid carbon dioxide supply step for supplying the liquid carbon dioxide.

[19] The spraying method according to any one of

[15] to

[18] , further comprising a liquid carbon dioxide supply step for supplying the liquid carbon dioxide and a stock solution supply step for supplying the stock solution.

[20] The spraying method according to any one of

[15] to

[19] , wherein in the mixed liquid obtained in the mixing step, the stock solution is dissolved or dispersed in the liquid carbon dioxide.

[21] The spraying method according to any one of

[15] to

[20] , wherein the stock solution is at least one selected from the group consisting of lemon oil, essential oil components, algae oil, and paint.

[22] The spraying method according to any one of

[15] to

[21] , wherein in the pressure-resistant vessel, the mass ratio of the stock solution to liquid carbon dioxide (stock solution / liquid carbon dioxide) is 0.01 to 0.99.

[23] The spraying method according to any one of

[15] to

[22] , wherein the droplet size of the atomized stock solution sprayed in the spraying step is 0.10 nm or more and 0.50 μm.

[0009] According to the present invention, it is possible to provide a spraying apparatus and spraying method that efficiently forms a fine mist of undiluted liquid in a simple manner.

[0010] Figure 1 is a schematic diagram showing a spraying device of the first embodiment. Figure 2 is a schematic diagram showing another embodiment of the spraying device of the first embodiment. Figure 3 is a schematic diagram showing a spraying device of the second embodiment. Figure 4 is a schematic diagram showing a spraying device of the third embodiment. Figure 5 is a diagram showing the relationship between the amount of limonene (g) sprayed and the amount of carbon dioxide gas (L) in Example 1 and Comparative Example 1. Figure 6 is a phase diagram of the two components carbon dioxide versus limonene.

[0011] The present embodiment will be described in detail below with reference to the drawings as appropriate. The drawings used in the following description may be enlarged for convenience to clearly illustrate the features of the present invention, and the dimensional ratios of each component may differ from those in reality. The materials, dimensions, etc., exemplified in the following description are examples only, and the present invention is not limited to them. It can be implemented with appropriate modifications without altering its essence.

[0012] (Spraying device) [First embodiment] The spraying device of the first embodiment includes a pressure vessel 4 and a spray unit 2 connected to the pressure vessel 4, as shown in Figure 1. The pressure vessel 4 contains a mixed liquid 6 obtained by mixing a stock solution and liquid carbon dioxide. The spray unit 2 sprays the mixed liquid in a mist form. The temperature range inside the pressure vessel 4 is above the triple point temperature of carbon dioxide and below the critical temperature. The carbon dioxide in the pressure vessel may be in a subcritical or high-pressure liquid state, and it is preferable that the pressure range in the pressure vessel is 0.1 MPa or more and 50 MPa or less, and the temperature range in the pressure vessel is -57°C or more and 31°C or less. Note that subcritical is a state in which temperature and pressure exist below the critical point, and is not supercritical. High-pressure liquid is a state in which pressure is above the triple point and below the critical temperature exists as a liquid. The spraying device of this embodiment may further include means for controlling the temperature or pressure of the pressure vessel to the above temperature range and pressure range. A pipe (not shown) may be provided between the injection unit and the pressure vessel, and the mixed liquid may be supplied from the pressure vessel to the injection unit through the pipe. In this embodiment, the spraying device may be such that the pressure vessel 4 is filled with the mixed liquid 6, as shown in the spraying device 1 of Figure 1, or the pressure vessel 40 may contain the mixed liquid 60 and carbon dioxide gas 80, as shown in the spraying device 10 of Figure 2. If the pressure vessel 4 further contains carbon dioxide gas, it is preferable that the carbon dioxide gas and the liquid carbon dioxide are in a gas-liquid equilibrium state. As shown in the spraying device 10 of Figure 2, if the mixed liquid 60 and carbon dioxide gas 80 are present, the amount of carbon dioxide gas 80 (volume ratio in the pressure vessel 4) may be 1 volume% or more, 5 volume% or more, 10 volume% or more, or 30 volume% or more. It may also be 80 volume% or less, 60 volume% or less, or 40 volume% or less.

[0013] [Pressure Vessel] The pressure vessel 4 may have a mixed liquid outlet for introducing the mixed liquid into the injection unit and a liquid carbon dioxide supply port for supplying the liquid carbon dioxide to the pressure vessel (not shown). The mixed liquid outlet and the liquid carbon dioxide supply port may be a single opening formed at the same location in the pressure vessel 4. In this case, liquid carbon dioxide can first be supplied to the pressure vessel to prepare the mixed liquid of the stock solution and liquid carbon dioxide, and then the mixed liquid can be supplied to the injection unit from the same opening. Alternatively, the mixed liquid outlet and the liquid carbon dioxide supply port may be two openings formed at different locations in the pressure vessel 4. In this case, liquid carbon dioxide can first be supplied to the pressure vessel 4 through the liquid carbon dioxide supply port to prepare the mixed liquid of the stock solution and liquid carbon dioxide, and then the mixed liquid can be supplied to the injection unit from the mixed liquid outlet. Furthermore, the supply of liquid carbon dioxide and the supply of the mixed liquid may be performed alternately in stages, such as in a batch system, or they may be supplied simultaneously, such as in a continuous system.

[0014] The carbon dioxide in the pressure vessel 4 may be in a subcritical or high-pressure liquid state. Furthermore, the pressure range in the pressure vessel may be 0.1 MPa or more and 50 MPa or less, and the temperature range in the pressure vessel may be -57°C or more and 31°C or less. Also, the pressure range in the pressure vessel may exceed the triple point pressure of carbon dioxide but be below the critical pressure. As long as the carbon dioxide in the pressure vessel 4 is maintained in a liquid state, the pressure range and temperature range can be appropriately selected depending on the application. For example, if there is a pressure limit for the pressure vessel 4, the pressure range in the pressure vessel 4 may be 0.55 MPa or more and 4.0 MPa or less, and the temperature range may be -57°C or more and 0°C or less, or the pressure range may be 0.55 MPa or more and 2.0 MPa or less, and the temperature range may be -57°C or more and -20°C or less, or further, the pressure range may be 0.55 MPa or more and 1.0 MPa or less, and the temperature range may be -57°C or more and -40°C or less. A known method can be used to control the temperature of the pressure vessel 4 at a low temperature. For example, the pressure vessel 4 can have walls with an insulating structure. Also, for example, when controlling the temperature to 0°C or below, a refrigerant can be used to control the temperature of the pressure vessel 4 to 0°C or below.

[0015] Furthermore, for example, when the temperature range of the pressure vessel 4 is near room temperature, the pressure range in the pressure vessel 4 may be 4.2 MPa or more and 7.0 MPa or less, and the temperature range in the pressure vessel 4 may be 10°C or more and 30°C or less, or the pressure range may be 5.0 MPa or more and 6.5 MPa or less and the temperature range may be 15°C or more and 25°C or less, or the pressure range may be 5.5 MPa or more and 6.5 MPa or less and the temperature range may be 20°C or more and 25°C or less. For example, in the embodiment described later, a liquefied carbon dioxide cylinder was used as a liquid carbon dioxide supply source. The temperature range of the pressure vessel 4 was set to room temperature of 25°C and controlled to the same pressure as the liquefied carbon dioxide cylinder pressure of 6.3 MPa (25°C). A mixed solution was prepared by mixing the undiluted limonene (main component of lemon oil) in the container with liquid carbon dioxide.

[0016] The temperature range and pressure range of the pressure vessel 4 may be the same or different in the mixed liquid preparation process and the mixed liquid supply process, respectively. For example, in the mixed liquid preparation process, the temperature range may be controlled to room temperature from the viewpoint of efficiently mixing the stock solution and liquid carbon dioxide, while in the mixed liquid supply process, the temperature range may be controlled to 0°C or below.

[0017] The pressure-resistant container 4 may further have a concentrate supply port for supplying the concentrate. The concentrate can be supplied to the pressure-resistant container through the concentrate supply port.

[0018] The pressure vessel 4 may have a pressure-resistant structure that can withstand internal pressures at least equal to the critical pressure of carbon dioxide. From the viewpoint of reducing the cost of the device while achieving the objectives of the present invention, it is sufficient for the pressure vessel to have a pressure-resistant structure that can withstand internal pressures below the critical pressure of carbon dioxide, and it is not necessary to have a pressure-resistant structure that can withstand pressures above the critical pressure of carbon dioxide. The maximum operating pressure of the pressure vessel 4 may be 2 MPa or more and less than the critical pressure of carbon dioxide. For example, the maximum operating pressure may be 7 MPa or less, or 6.5 MPa or less. Alternatively, in usage conditions where the temperature range is a low temperature range (0°C or below, or -20°C or below), the maximum operating pressure may be 5.0 MPa or less, 4.0 MPa or less, or 3.0 MPa or less. Furthermore, the maximum operating pressure may be, for example, 1.0 MPa or more, or 2.0 MPa or more. Examples of the pressure vessel 4 include pressure vessels having the various maximum operating pressures described above. A known structure can be used for the pressure vessel structure having the maximum operating pressure, and there are no particular limitations. Examples of the pressure vessel 4 include pressure vessels equipped with pressure reducing valves and safety valves that maintain the various maximum operating pressures mentioned above.

[0019] <Mixed Solution> The mixed solution 6 may be a solution obtained by dissolving the stock solution in liquid carbon dioxide, or a dispersion obtained by dispersing the stock solution in liquid carbon dioxide. The stock solution contained in the mixed solution 6 may be soluble in liquid carbon dioxide or dispersible in liquid carbon dioxide, and is not particularly limited. Examples of the stock solution include lemon oil, essential oil components, algae oil, lubricating oil for machine cutting, hair care and styling agents, skin care agents, cooling agents, fragrances, cleaning agents, various coating agents, pesticide compositions, and paints. The stock solution may be lemon oil, essential oil components, algae oil, or paints. In the pressure vessel, the mass ratio of the stock solution to the liquid carbon dioxide (stock solution / liquid carbon dioxide) is preferably 0.01 to 0.99.

[0020] [Injection Unit] The injection unit 2 according to this embodiment injects the mixed liquid 6 introduced from the pressure vessel 4 to form a mist of the mixed liquid, and as the liquid carbon dioxide evaporates, it forms fine mist droplets (mist) of the undiluted liquid. The injection unit 2 is a member for discharging the mixed liquid 6 and preferably mainly comprises a nozzle part with discharge holes and a valve mechanism for operating the injection opening and closing. The mixed liquid is discharged from the discharge holes. The number and shape of the discharge holes are not particularly limited. There may be multiple discharge holes. The shape of the discharge holes may be circular, angular, etc. In the spraying device 1 of this embodiment, when the valve mechanism is opened, the pressure vessel 4 is opened. As a result, the inside of the pressure vessel 4 and the injection unit 2 or the outside are in communication. The mixed liquid 6 is sent to the injection member and then discharged from the discharge holes. The injection unit 2 may further have an introduction pipe. The mixed liquid 6 can be introduced into the injection unit 2 from the bottom of the pressure vessel 4 using the introduction pipe. In particular, as shown in Figure 2, if the pressure vessel 40 has a gas phase portion consisting of carbon dioxide gas 80 (sometimes called "carbon dioxide") and a mixed liquid 60, and has a gas phase portion consisting of carbon dioxide gas 80 and a liquid phase portion 60 consisting of the mixed liquid, the liquid surface of the mixed liquid 60 is pressed down by the pressure of the carbon dioxide gas. As a result, the mixed liquid 60 passes through the introduction pipe and is sent to the injection member, and then discharged from the discharge hole.

[0021] The spraying device 1 of this embodiment will be further described using the following examples of the second and third embodiments. The spraying device of this embodiment is not limited to these disclosures. Also, the description of parts that are the same as in the first embodiment will be omitted.

[0022] [Second Embodiment] The spraying device 100 of the second embodiment includes a pressure vessel 14 and a spray unit 12 directly connected to the pressure vessel 14, as shown in Figure 3. The pressure vessel 14 contains a mixed liquid 16 containing a stock solution and liquid carbon dioxide, and carbon dioxide gas 18. The spray unit 12 includes an introduction pipe 12-1, a valve 12-2, a spray port 12-3, and a spray operation unit 12-4. The mixed liquid is introduced into the spray unit 12 from the bottom of the pressure vessel 14 through the introduction pipe 12-1. The valve 12-2 is installed between the introduction pipe 12-1 and the spray port 12-3. The spray operation unit 12-4 is operated to open and close the valve 12-2 and operate the spray. As the spray unit 12 of the spraying device 100 of the second embodiment, for example, a known spray or aerosol spraying mechanism can be used. Furthermore, since a mixture containing liquid carbon dioxide is used, a heating mechanism may be included in the injection unit 12 as needed. The heating mechanism can be, for example, a heating mechanism for a liquid carbon dioxide gas cylinder valve. This is because the temperature near the injection port may decrease depending on the temperature, pressure, injection volume, and injection frequency of the pressure vessel 14. The pressure vessel 14 may be a pressure vessel with a maximum operating pressure of 7.5 MPa, a pressure vessel with a maximum operating pressure of 7 MPa, or a pressure vessel with a maximum operating pressure of 6.5 MPa. In that case, in a normal room temperature environment (for example, 25°C), the carbon dioxide contained in the mixture 16 is in the liquid phase, i.e., it is liquid carbon dioxide. Also, the volume ratio of the mixture and carbon dioxide (mixture:carbon dioxide) may be any supply volume ratio as long as it is such that a homogeneous phase state is formed when mixed. The pressure vessel 14 may also be provided with a safety mechanism such as a pressure adjustment safety valve. For example, a safety valve with a pressure 0.5 MPa lower than the maximum operating pressure may be set. For example, if a pressure vessel with a maximum operating pressure of 7.5 MPa is used, a safety valve with a pressure of 7 MPa may be provided to prevent an abnormal pressure increase due to temperature rise. In that case, even if the ambient temperature exceeds 30°C, the internal pressure of the pressure vessel 14 will not exceed the critical pressure of carbon dioxide, and carbon dioxide will not become a supercritical fluid.The internal temperature of the pressure vessel 14 can be maintained at, for example, -20°C or below by using an insulating layer or a cooling mechanism. In this case, a pressure vessel 14 with a maximum operating pressure of 2.5 MPa may be used.

[0023] [Third Embodiment] The spraying device 200 of the third embodiment includes, as shown in Figure 4, a pressure-resistant container 24 and an injection unit 22 connected to the pressure-resistant container 24 through a first pipe 23-1. The spraying device 200 further includes a liquefied carbon dioxide gas cylinder 25, a valve (V0) 21, a safety valve 27, and a second pipe 23-2. Liquid carbon dioxide is supplied from the liquefied carbon dioxide gas cylinder 25 to the pressure-resistant container 24 through the second pipe 23-2. The injection unit 22 includes a valve (v1) 22-1, a valve (v2) 22-2, and an injection port 22-3. The liquefied carbon dioxide gas cylinder 25 can be, for example, a commercially available 6.3 MPa pressure liquid carbon dioxide gas cylinder. The liquid carbon dioxide is supplied to the pressure-resistant container 24, and a pressure of 6.3 MPa is maintained. The spraying device 200 of the third embodiment can prepare a mixed solution after introducing a stock solution into the pressure-resistant container 24 and then introducing the liquid carbon dioxide. The spraying device 200 of the third embodiment may also have a mechanism (not shown) for supplying a stock solution. In that case, the supply of liquid carbon dioxide and the supply of stock solution may be performed continuously or intermittently, and the amount of mixed solution sprayed may be replenished. Examples of the liquefied carbon dioxide gas cylinder include commercially available liquefied carbon dioxide gas cylinders manufactured by Taiyo Nippon Sanso Corporation and Resonac Corporation. Examples of the first pipe 23-1 and second pipe 23-2 include metal coils manufactured by Swagelok Corporation. Examples of the valves (v0) 21, (v1) 22-1, and (v2) 22-2 include needle valves and metering valves manufactured by Swagelok Corporation. Examples of the safety valve 27 include safety valves manufactured by JASCO Corporation.

[0024] [Applications of the spraying device] Possible applications of the spraying device of this embodiment include, for example, cosmetic sprays such as foam spray shampoos, fragrance and perfume sprays, deodorizing sprays, spray painting, and flavoring of food.

[0025] (Spraying Method) The spraying method of one embodiment of the present invention includes the following two steps: (1) A mixing step of mixing a stock solution and liquid carbon dioxide. (2) A spraying step of spraying the mixture obtained in the mixing step in a mist. The temperature range of the mixture is above the triple point temperature of carbon dioxide and below the critical temperature. It is preferable that the liquid carbon dioxide is in a subcritical state rather than a supercritical state. It is preferable that the pressure range of the mixture is 0.1 MPa or more and 50 MPa or less, and the temperature range in the pressure vessel is -57°C or more and 31°C or less.

[0026] The spraying method of this embodiment may further include one or two of the following two steps: (3) a liquid carbon dioxide supply step of supplying liquid carbon dioxide; (4) a stock solution supply step of supplying the stock solution.

[0027] In the spraying method of this embodiment, the terms "stock solution," "mixed solution," "mass ratio of stock solution to liquid carbon dioxide (stock solution / liquid carbon dioxide)," and "droplet size of the atomized stock solution sprayed in the spraying step" have the same meaning as those described in the spraying apparatus of the first to third embodiments described above. The spraying method of this embodiment may also use the spraying apparatus of the first to third embodiments.

[0028] (Example 1) Example 1 used the spraying apparatus 200 of the third embodiment shown in Figure 4. 5.8 g of limonene, the main component of lemon oil, was placed in the pressure vessel 24. Liquid carbon dioxide was supplied to the pressure vessel 24 from a liquefied carbon dioxide gas cylinder to prepare a mixture of limonene and carbon dioxide. The valves (v1) 22-1 and (v2) 22-2 were controlled to spray the prepared mixture from the nozzle. The amount of limonene sprayed was measured using the measurement method described below, and the flow rate of the carbon dioxide gas (after evaporation of liquid carbon dioxide) was measured at the same time. The results are shown in Figure 5. Details of the apparatus, experimental conditions for the spraying experiment, and evaluation method are described below.

[0029] [Spraying Equipment] Liquefied carbon dioxide gas cylinder: Resonac liquefied carbon dioxide gas cylinder (99.5% purity), pressure value at room temperature: 6.3 MPa Pressure-resistant container 24: JASCO EV series Nozzle 22-3: Swagelok needle valve Valve (v0) 21: Swagelok needle valve Valve (v1) 22-1: Swagelok needle valve Valve (v2) 22-2: Swagelok needle valve Safety valve 27: JASCO safety valve First piping 23-1: GL Science 1 / 16 inch stainless steel coil Second piping 23-2: GL Science 1 / 16 inch stainless steel coil

[0030] [Experimental conditions for limonene injection experiment] Amount of limonene to be added: 5.8 g Volume of extraction cell (pressure-resistant container 24): 50 cm³ ３ Pressure vessel 24: Internal temperature: 25°C, Pressure: 6.3 MPa, Flow rate: 4 L / min (SATP: standard ambient temperature and pressure)

[0031] [Evaluation Method] <Method for measuring the amount of limonene ejected> The amount of limonene ejected was collected using a trap cooled with ice water, and its weight was directly measured using a balance.

[0032] <Method for measuring carbon dioxide flow velocity and flow rate> The carbon dioxide flow velocity and flow rate were measured using a dry flow meter (Shinagawa DC-2) after the carbon dioxide was brought to atmospheric pressure.

[0033] (Comparative Example 1) The injection experiment was conducted in the same manner as in Example 1, except that the internal temperature of the pressure vessel 24 was set to 40°C (warm bath). The carbon dioxide flow rate and the amount of limonene ejected were evaluated in the same manner as in Example 1, and the results are shown in Figure 5.

[0034] (Discussion) From the results in Figure 5, under the temperature and pressure conditions of Example 1 (25°C, 6.3 MPa), carbon dioxide existed as a liquid in the pressure vessel 24, and a mixture of this liquid carbon dioxide and limonene was obtained. In contrast, under the temperature conditions of Comparative Example 1 (40°C), carbon dioxide existed as a supercritical fluid in the pressure vessel 24, and a mixture of this supercritical carbon dioxide fluid and limonene was obtained. From the results in Figure 5, under the temperature and pressure conditions in which liquid carbon dioxide exists, the amount of limonene ejected was dramatically improved compared to that of supercritical carbon dioxide.

[0035] Figure 6 shows the phase diagram of a two-component system of carbon dioxide and limonene. As shown in Figure 6, the phase equilibrium relationship is such that liquid carbon dioxide has a higher mixing ratio with limonene than supercritical carbon dioxide fluid. Under supercritical conditions such as in Comparative Example 1, not only is high-temperature operation required, but at 6.3 MPa, two phases (gas-liquid phase) appear, and high spray efficiency cannot be obtained unless the liquid phase is effectively utilized. On the other hand, under the conditions of liquid carbon dioxide as in Example 1 (subcritical conditions), at 6.3 MPa, a homogeneous phase is formed under all composition conditions, so lemon oil of any composition can be discharged (sprayed) all at once. Furthermore, when the pressure cell (pressure vessel 24) is cooled, the phase equilibrium curve shifts further to the lower pressure side, so more effective spraying can be expected with simpler operation. In addition, under experimental conditions below room temperature, the fact that lemon oil is sensitive to heat is also an important factor.

[0036] 1, 10, 100, 200: Spraying device 2, 20, 12, 22: Spray section 4, 40, 14, 26: Pressure vessel 6, 60, 16, 26: Mixture containing undiluted solution and liquid carbon dioxide 12-3, 22-3: Spray nozzle 12-4: Spray operation section 12-2: Valve 12-1: Inlet pipe 18: Carbon dioxide gas 21: Valve v0 22-1: Valve v1 22-2: Valve v2 23-1: First piping 23-2: Second piping 25: Liquefied carbon dioxide gas cylinder 27: Safety valve

Claims

1. A spraying device comprising a pressure vessel and a spray unit connected to the pressure vessel, wherein the pressure vessel contains a mixed liquid obtained by mixing a stock solution and liquid carbon dioxide, the spray unit sprays the mixed liquid in a mist, and the temperature range of the pressure vessel is above the triple point temperature of carbon dioxide and below the critical temperature.

2. The spraying apparatus according to claim 1, wherein the carbon dioxide in the pressure vessel is in a subcritical or high-pressure liquid state.

3. The spraying apparatus according to claim 1 or 2, wherein the pressure range in the pressure vessel is 0.1 MPa or more and 50 MPa or less, and the temperature range in the pressure vessel is -57°C or more and 31°C or less.

4. The spraying device according to claim 1 or 2, wherein the maximum operating pressure of the pressure vessel is 2 MPa or more and less than the critical pressure of carbon dioxide.

5. The spraying apparatus according to claim 1 or 2, wherein the pressure range of the pressure-resistant vessel exceeds the triple point pressure of carbon dioxide and is less than the critical pressure.

6. The spraying apparatus according to claim 1 or 2, wherein the pressure vessel further contains carbon dioxide gas, and the carbon dioxide gas and the liquid carbon dioxide are in a gas-liquid equilibrium state.

7. The spraying device according to claim 1 or 2, wherein the spraying unit and the pressure vessel are directly connected, and the mixed liquid is supplied from the pressure vessel to the spraying unit.

8. The spraying device according to claim 1 or 2, further comprising piping between the spraying unit and the pressure vessel, wherein the mixed liquid is supplied from the pressure vessel to the spraying unit through the piping.

9. The spraying device according to claim 1 or 2, wherein the pressure vessel has a mixed liquid outlet for introducing the mixed liquid into the spraying section and a liquid carbon dioxide supply port for supplying the liquid carbon dioxide to the pressure vessel, and liquid carbon dioxide is supplied to the pressure vessel through the liquid carbon dioxide supply port.

10. The spraying device according to claim 1 or 2, wherein the pressure vessel has a mixed liquid outlet for introducing the mixed liquid into the spraying section, a liquid carbon dioxide supply port for supplying the liquid carbon dioxide, and a concentrate supply port for supplying the concentrate, and the liquid carbon dioxide is supplied to the pressure vessel through the liquid carbon dioxide supply port, and the concentrate is supplied to the pressure vessel through the concentrate supply port.

11. The spraying apparatus according to claim 1 or 2, wherein in the mixed liquid, the stock solution is dissolved or dispersed in the liquid carbon dioxide.

12. The spraying apparatus according to claim 1 or 2, wherein the stock solution is at least one selected from the group consisting of lemon oil, essential oil components, algal oil, paint, etc.

13. The spraying apparatus according to claim 1 or 2, wherein the mass ratio of the stock solution to the liquid carbon dioxide (stock solution / liquid carbon dioxide) in the pressure-resistant container is 0.01 to 0.

99.

14. The spraying apparatus according to claim 1 or 2, wherein the droplet size of the atomized undiluted liquid sprayed from the spraying unit is 0.1 nm or more and 0.5 μm.

15. A spraying method comprising a mixing step of mixing a stock solution and liquid carbon dioxide inside a pressure vessel, and a spraying step of spraying the mixture obtained in the mixing step in a mist, wherein the temperature range of the mixture is above the triple point temperature of carbon dioxide and below the critical temperature.

16. The spraying method according to claim 15, wherein the liquid carbon dioxide is in a subcritical state or a high-pressure liquid.

17. The spraying method according to claim 15 or 16, wherein the pressure range of the mixed liquid in the pressure-resistant container is 0.1 MPa or more and 50 MPa or less, and the temperature range is -57°C or more and 31°C or less.

18. The spraying method according to claim 15 or 16, further comprising a liquid carbon dioxide supply step of supplying the liquid carbon dioxide.

19. The spraying method according to claim 15 or 16, further comprising a liquid carbon dioxide supply step for supplying the liquid carbon dioxide and a stock solution supply step for supplying the stock solution.

20. The spraying method according to claim 15 or 16, wherein in the mixed liquid obtained in the mixing step, the stock solution is dissolved or dispersed in the liquid carbon dioxide.

21. The spraying method according to claim 15 or 16, wherein the stock solution is at least one selected from the group consisting of lemon oil, essential oil components, algal oil, and paint.

22. The spraying method according to claim 15 or 16, wherein in the pressure-resistant vessel, the mass ratio of the stock solution to the liquid carbon dioxide (stock solution / liquid carbon dioxide) is 0.01 to 0.

99.

23. The spraying method according to claim 15 or 16, wherein the droplet size of the atomized stock solution sprayed in the spraying step is 0.1 nm or more and 0.5 μm.

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