Production device and production method for gas hydrate-containing ices

Abstract

To provide a novel production device and production method for making gas hydrate-containing ices in which distribution of gas hydrate is less biased.SOLUTION: A production device for gas hydrate-containing ices comprises: a circulation path through which a raw material solution circulates; a gas-liquid mixing unit that is provided in the circulation path and mixes the raw material solution with a raw material gas; a gas hydrate production unit that is provided in the circulation path downstream of the gas-liquid mixing unit, and produces gas hydrate from a mixture of the raw material solution and the raw material gas; and a freezing unit that freezes a gas hydrate slurry containing the gas hydrate and a portion of the raw material solution to produce gas hydrate-containing ices.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for producing gas hydrate-containing ice. [Background technology]

[0002] In recent years, development of gas hydrate-containing ice has been progressing as a new food ingredient. Gas hydrate generally refers to ice-like solid crystals formed by gases such as methane, ethane, and carbon dioxide and water.

[0003] Gas hydrate-containing ice is produced, for example, by the method described in Patent Document 1. The method described in Patent Document 1 is a so-called batch method, in which all of the acidulant-containing water prepared for producing gas hydrate-containing ice is sent to the next step.

[0004] Patent Document 2 describes an apparatus for producing hydrate in a circulating manner. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-148370 [Patent Document 2] Japanese Patent Publication No. 2020-081964 Summary of the Invention [Problem to be solved by the invention]

[0006] Gas hydrate-containing ice produced by a typical batch method is cooled directly in the gas hydrate production vessel, resulting in a structure with more gas hydrate at the bottom and less gas hydrate at the top, which creates a problem of uneven distribution of gas hydrate within the batch. In addition, although the acidulant-containing CO2 hydrate produced by the batch method is removed, some of the solution remains in the slurry production vessel. Because the amount of water contained in the remaining solution decreases due to the formation of hydrate, the concentration of the remaining solution becomes higher than the concentration before the hydrate formation. Therefore, when attempting to continuously produce gas hydrate-containing ice, the remaining solution increases the concentration of the solution in the slurry production vessel, resulting in variations in the taste of the gas hydrate-containing ice between batches. Furthermore, in the batch method, the hydrate formation reaction proceeds while stirring the water and gas, but the amount of stirring increases during mass production, which creates the problem of increased energy required during stirring.

[0007] Therefore, an object of the present invention is to provide a novel manufacturing apparatus and manufacturing method for producing gas hydrate-containing ice with little bias in the distribution of gas hydrate. Another object of the present invention, in a preferred embodiment, is to provide a novel manufacturing apparatus and manufacturing method for producing gas hydrate-containing ice with little variation in taste when producing gas hydrate-containing ice using a solution. Another object of the present invention is to provide a novel manufacturing apparatus and manufacturing method that requires little stirring energy when generating gas hydrate. [Means for solving the problem]

[0008] The present invention that solves the above problems is the following [1] to

[13] . [1] An apparatus for producing gas hydrate-containing ice, comprising: a circulation path through which a raw material solution circulates; a gas-liquid mixing section provided in the circulation path and mixing the raw material solution with a raw material gas; a gas hydrate production section provided in the circulation path downstream of the gas-liquid mixing section and producing gas hydrate from a mixed liquid of the raw material solution and the raw material gas; and a freezing section that freezes a gas hydrate slurry containing the gas hydrate and a portion of the raw material solution to produce gas hydrate-containing ice.

[0009] [2] The apparatus for producing gas hydrate-containing ice according to [1], further comprising a separation section between the gas hydrate production section and the freezing section, which separates the gas hydrate slurry from the remaining raw solution.

[0010] [3] The apparatus for producing gas hydrate-containing ice according to [2], further comprising a dehydration unit for dehydrating the gas hydrate slurry.

[0011] [4] The apparatus for producing gas hydrate-containing ice according to [3], wherein the separation unit separates the gas hydrate slurry from the residual raw solution containing the residual raw gas.

[0012] [5] The apparatus for producing gas hydrate-containing ice according to [4], further comprising a gas-liquid separation unit that separates the remaining raw solution containing the remaining raw gas from the remaining raw solution.

[0013] [6] The apparatus for producing gas hydrate-containing ice according to any one of [1] to [5], further comprising a concentration adjusting unit for adjusting the concentration of the raw material solution.

[0014] [7] The method for producing gas hydrate-containing ice according to any one of [1] to [5], wherein the separation section is provided with a baffle plate.

[0015] [8] A method for producing gas hydrate-containing ice, comprising: a gas-liquid mixing step of mixing a raw material gas with a raw material solution; a gas hydrate production step of producing a gas hydrate from a mixed liquid of the raw material solution and the raw material gas; and a freezing step of freezing a gas hydrate slurry containing the gas hydrate and a portion of the raw material solution to produce gas hydrate-containing ice.

[0016] [9] The method for producing gas hydrate-containing ice according to [8], in which the gas-liquid mixing step, the gas hydrate production step, and the freezing step are repeatedly performed, further comprising a solid-liquid separation step of separating the gas hydrate slurry from a remaining raw material solution, and a dehydration step of dehydrating the gas hydrate slurry.

[0017]

[10] The method for producing gas hydrate-containing ice according to [9], which includes mixing the remaining raw solution with the raw solution and using it in the gas-liquid mixing step, and further includes a concentration adjustment step of adjusting the concentration of the raw solution mixed with the remaining raw solution.

[0018]

[11] The method for producing gas hydrate-containing ice according to any one of [8] to

[10] , wherein the raw material solution is an aqueous solution containing one or more components selected from the group consisting of flavorings, sweeteners, acidulants, emulsifiers, stabilizers, salts, and amino acids.

[0019]

[12] The method for producing gas hydrate-containing ice according to any one of [8] to

[10] , further comprising a gas-liquid separation step of separating the remaining raw solution from the remaining raw gas, and using the remaining raw gas in the gas-liquid mixing step.

[0020]

[13] The method for producing gas hydrate-containing ice according to any one of [8] to

[10] , further comprising an ice-crushing step of crushing the gas hydrate-containing ice produced in the freezing step to obtain a plurality of small pieces. [Effects of the Invention]

[0021] According to the present invention, it is possible to produce gas hydrate-containing ice with little bias in the distribution of gas hydrate. Furthermore, in a preferred embodiment of the present invention, it is possible to produce gas hydrate-containing ice with little variation in taste. Furthermore, in a preferred embodiment of the present invention, it is possible to provide a novel production apparatus and production method that require little stirring energy when generating gas hydrate. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is an explanatory diagram for explaining an overview of an apparatus and method for producing gas hydrate-containing ice according to one embodiment of the present invention. FIG. [Figure 2] 1 is a diagram illustrating a baffle plate according to an embodiment of the present invention. FIG. [Figure 3] 1 is a flowchart illustrating the flow of a method for producing gas hydrate-containing ice according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] 1 is an explanatory diagram for explaining an overview of an apparatus and method for producing gas hydrate-containing ice according to one embodiment of the present invention. First, an overview of the apparatus for producing gas hydrate-containing ice will be described with reference to FIG.

[0024] As shown in FIG. 1, the manufacturing apparatus 1 includes a circulation path 11, a raw material solution supply section 12, a raw material gas supply section 13, a gas-liquid mixing section 14, a gas hydrate generation section 15, a separation section 16, a freezing section 17, a gas-liquid separation section 18, a replenishment liquid supply section 19, a circulation pump 20, a dehydration treatment solution supply pipe 21, and a residual raw material gas supply pipe 22.

[0025] The circulation path 11 includes a plurality of circulation paths, such as a circulation path 111, a circulation path 112, a circulation path 113, a circulation path 114, a circulation path 115, and a circulation path .

[0026] The circulation path 111 communicates with the raw solution supply unit 12 and the circulation pump 20. The circulation path 112 communicates with the circulation pump 20 and the gas-liquid mixing unit 14. The circulation path 113 communicates with the gas-liquid mixing unit 14 and the gas hydrate production unit 15. The circulation path 114 communicates with the gas hydrate production unit 15 and the separation unit 16. The circulation path 115 communicates with the separation unit 16 and the gas-liquid separation unit 18. The circulation path 116 communicates with the gas-liquid separation unit 18 and the raw solution supply unit 12.

[0027] In FIG. 1 , solid arrows indicate the flow of the raw solution flowing through circulation path 11. Specifically, raw solution supplied from raw solution supply unit 12 to circulation path 111 is pumped into circulation path 112 by circulation pump 20 and flows into gas-liquid mixing unit 14. Then, the raw solution mixed with the raw gas in gas-liquid mixing unit 14 flows into gas hydrate production unit 15 via circulation path 113. Then, from gas hydrate production unit 15, a mixed solution containing raw solution, raw gas, and gas hydrate flows into separation unit 16 via circulation path 114. Here, gas hydrate slurry, which contains gas hydrate and a portion of the raw solution, of the mixed solution flows into freezing unit 17 by opening valve 162, and the remaining raw solution flows into gas-liquid separation unit 18 via circulation path 115. Then, the separated remaining raw gas and remaining raw solution are returned to raw solution supply unit 12 and used for the next generation of gas hydrate.

[0028] Here, the remaining raw material solution is the remaining raw material solution of the mixed solution that is not contained in the gas hydrate slurry. The remaining raw material gas is the remaining raw material gas in the mixed solution that is not contained in the gas hydrate slurry.

[0029] The raw material solution supply unit 12 includes a raw material solution tank 121. The raw material solution tank 121 contains the raw material solution. The flow rate of the raw material solution flowing out of the raw material solution tank 121 can be detected, for example, by a flow meter provided near the raw material solution tank 121 and on the circulation path 111. The flow rate of the raw solution flowing out of the raw solution tank 121 may also be detected based on the amount of the solution delivered by the circulation pump 20, which will be described later.

[0030] The raw material solution is not particularly limited as long as it can produce gas hydrate, but can be a solution containing components such as flavorings, sweeteners, acidulants, emulsifiers, stabilizers, salts, amino acids, coloring agents, dietary fiber, thickening polysaccharides, vitamins, minerals, and / or fruit juice, etc. Preferably, the raw material solution is an aqueous solution containing one or more components selected from the group consisting of flavorings, sweeteners, acidulants, emulsifiers, stabilizers, salts, and amino acids. According to the gas hydrate-containing ice manufacturing apparatus of the present invention, even if the raw material solution contains additives, gas hydrate-containing ice with little bias in the distribution of gas hydrate can be manufactured. In the present invention, raw water containing no additives can also be used as the raw material for gas hydrate-containing ice.

[0031] The circulation pump 20 circulates the raw material solution supplied from the raw material solution supply unit 12 to the circulation path 111, through the circulation path 112. The circulation pump 20 can also circulate the replenishment solution supplied from the replenishment solution supply unit 19 (described later) to the circulation path 111, through the circulation path 112. The circulation pump 20 is disposed between the circulation paths 111 and 112.

[0032] The raw material gas supply unit 13 includes a raw material gas tank 131, a raw material gas supply pipe 132, and a mass flow controller 133. The raw material gas tank 131 contains a raw material gas. The raw material gas flows from the raw material gas tank 131 into the raw material gas supply pipe 132 and is discharged from the raw material gas supply pipe 132 to the circulation path 112. The mass flow controller 133 controls the flow of the raw material gas from the raw material gas supply pipe 132 to the circulation path 112.

[0033] The raw material gas is not particularly limited as long as it can produce a gas hydrate, but is preferably a gas that can be used in food. Examples include carbon dioxide, helium, oxygen, nitrogen, nitrous oxide, and argon. Examples of the gas hydrate that can be produced include carbon dioxide hydrate, helium hydrate, and oxygen hydrate. The raw material gas in the present invention is preferably carbon dioxide.

[0034] The raw material gas supplied from raw material gas supply unit 13 is preferably at a pressure of 3 MPa. By supplying raw material gas from raw material gas supply unit 13, the pressure inside the gas hydrate-containing ice manufacturing apparatus is kept constant.

[0035] Here, an example of the flow of the raw material gas in the production apparatus of the present invention will be described. First, the raw material gas supplied from the raw material gas supply unit 13 is supplied to the circulation path 112 via the raw material gas supply pipe 132. Then, it flows into the gas-liquid mixing unit 14 via the circulation path 112. In the gas-liquid mixing unit 14, the raw material gas is mixed with the raw material solution and flows into the gas hydrate production unit 15 via the circulation path 113. Thereafter, the remaining raw material gas, dissolved in the remaining raw material solution and / or mixed with the remaining raw material solution in the form of bubbles, is separated from the gas hydrate slurry in the separation unit 16, and then flows into the gas-liquid separation unit 18 via the circulation path 115. The remaining raw material gas separated from the remaining raw material solution in the gas-liquid separation unit 18 flows into the raw material solution tank 121 via the circulation path 116. Then, the remaining raw material gas is returned to the circulation path 112 via the remaining raw material gas supply pipe 22 and used for the production of the next gas hydrate. The gas hydrate slurry may contain a portion of the raw material gas that was not used in the production of gas hydrate dissolved in a portion of the raw material solution and / or in the form of bubbles, and a portion of the raw material gas may flow into the freezing section 17 together with the gas hydrate slurry. Furthermore, the remaining raw material gas that has not been separated from the remaining raw material solution in the gas-liquid separator 18 may flow into the raw material solution tank 121 in a state where it is dissolved in the remaining raw material solution.

[0036] The raw material solution and raw material gas supplied from the raw material solution supply unit 12 and raw material gas supply unit 13 flow into the gas-liquid mixing unit 14. The raw material solution supplied from the replenishment liquid supply unit 19 may also flow into the gas-liquid mixing unit 14 as the raw material solution. The gas-liquid mixing unit 14 mixes the raw material solution and raw material gas. Then, the gas-liquid mixing unit 14 outputs a mixed liquid of the raw material solution and raw material gas. Furthermore, the residual source gas separated in the gas-liquid separator 18, which will be described later, may flow into the gas-liquid mixer 14. In this case, the gas-liquid mixer 14 mixes the source solution, the source gas, and the residual source gas, and outputs a mixture of the source solution, the source gas, and the residual source gas.

[0037] The gas-liquid mixing section 14 is not particularly limited as long as it can sufficiently mix the raw material solution and the raw material gas, and examples thereof include a container with a stirring device, a static mixer such as a static mixer, etc. Alternatively, stirring blades or static blades may be provided, and the raw material solution and the raw material gas may be mixed by the resistance of the stirring blades or static blades. In the present invention, gas hydrate is continuously produced in gas hydrate production section 15, so that even when gas hydrate is mass-produced, the energy required for agitation is smaller than in batch production. Furthermore, while the energy efficiency of agitation of the product decreases as the scale of a batch production apparatus increases, the energy efficiency of agitation of the product improves with increasing scale in the production apparatus of the present invention.

[0038] The gas hydrate production section 15 is connected to the circulation path 113 and is provided downstream of the gas-liquid mixing section 14. The raw material solution and raw material gas mixed in the gas-liquid mixing section 14 flow into the gas hydrate production section 15. The gas hydrate production section 15 produces gas hydrate from the mixed solution of the raw material solution and raw material gas mixed in the gas-liquid mixing section 14. Then, the gas hydrate production section 15 outputs a mixed solution containing the raw material solution, raw material gas, and gas hydrate.

[0039] When the raw material gas is carbon dioxide (CO2), the gas hydrate production section 15 is preferably a cooled high-pressure reaction vessel capable of applying a pressure of 1 to 5 MPa, preferably 1.3 to 3.2 MPa, to the raw material solution and the raw material gas at a temperature of 0 to 10°C. Under the above conditions, gas hydrate (CO2 hydrate) can be produced.

[0040] The separation unit 16 includes a storage tank 161, a valve 162, and a baffle plate 163. The mixed solution from the gas hydrate production unit 15 flows into the storage tank 161. Then, the mixed solution is separated into a gas hydrate slurry containing the gas hydrate produced in the gas hydrate production unit 15 and a portion of the raw solution, and the remaining raw solution. Due to gravity, the gas hydrate settles to the bottom of the storage tank 161, and the gas hydrate slurry containing the gas hydrate that has settled to the bottom of the storage tank 161 and a portion of the raw solution flows out into the freezing section 17 by opening the valve 162. Furthermore, the remaining raw material solution flows out from the separation section 16 into the circulation path 115 .

[0041] Here, it is more preferable that the separation unit 16 separates the gas hydrate slurry from the residual raw material solution containing the residual raw material gas. Note that the raw material gas may flow out to the freezing unit 17 together with the gas hydrate slurry in a state where it is dissolved in the raw material solution contained in the gas hydrate slurry or in a state where it is not dissolved as bubbles.

[0042] In the present invention, the separation section 16 is preferably provided with a baffle plate 163 for reducing the flow rate of the mixed solution containing the raw material solution, raw material gas, and gas hydrate. With the above configuration, the flow of the mixed solution flowing out from the gas hydrate production section 15 becomes gentler in the separation section 16, and the gas hydrate can be made to settle more easily to the bottom of the storage tank 161. Without the baffle plate 163, the gas hydrate would rise up in the separation section 16, making it difficult for the gas hydrate to settle.

[0043] The baffle plates 163 are not particularly limited in shape, installation angle, number of plates installed, etc., as long as they can suppress the flow rate of the mixed solution. Examples of the shape of the baffle plates 163 include flat plates and perforated plates (punched plates, etc.). Perforated plates (punched plates, etc.) have holes large enough to allow gas hydrate to pass through without clogging. The baffle plates 163 may be installed horizontally to the ground, or may be installed at an angle so that gas hydrate does not accumulate on the baffle plates 163. The baffle plates 163 are preferably installed in the separation section 16 as shown in FIG. 1, but may also be installed in the circulation path 114. In FIG. 1, the baffle plate 163 is installed horizontally to the ground near the connection hole with the circulation path 114 in the separation section 16.

[0044] When installing baffle plates in the circulation path 114, it is possible to install a general baffle plate 23a as shown in Fig. 2(a), to install a plurality of baffle plates 23b in a maze shape as shown in Fig. 2(b), or to install a perforated plate (such as a punched plate) baffle plate 23c as shown in Fig. 2(c). Any other baffle plate may be installed as long as it allows the raw material solution, raw material gas, and mixed solution containing gas hydrate to flow through the circulation path 114 and can suppress the flow rate.

[0045] Freezing unit 17 freezes the gas hydrate slurry to produce gas hydrate-containing ice. There are no particular limitations on the freezing unit 17 as long as it can produce gas hydrate-containing ice, but it is preferably a freezing device or the like that can freeze the gas hydrate slurry at a temperature condition of -5°C or lower. More preferably, it is a high-pressure freezing device that can freeze the gas hydrate slurry at a temperature condition of -5°C or lower. The gas hydrate-containing ice in the present invention refers to ice obtained by freezing the gas hydrate slurry.

[0046] In the present invention, it is preferable to dehydrate the gas hydrate slurry before freezing. In this case, a dehydration section having a dehydration function may be provided between the separation section 16 and the freezing section 17. Alternatively, a dehydration / freezing section having both a freezing function and a dehydration function may be provided.

[0047] In the dehydration treatment, a portion of the raw material solution contained in the gas hydrate slurry is separated. By adopting the above-mentioned configuration, the gas hydrate content can be increased.

[0048] As the dehydration method, a general dehydration method such as centrifugation, pressure separation, sedimentation separation, etc. can be used. The dehydration structure includes a structure capable of separating solids, and may be a general structure such as a sintered plate, mesh, filter paper, or filter. In the dehydration treatment of the present invention, it is preferable to inject the gas hydrate slurry into a dehydration device having a filter at one end, and then pressurize the gas hydrate slurry from the other end with a pressure means to filter it.

[0049] It is preferable to adjust the hydrate ratio of the gas hydrate-containing ice to a desired hydrate ratio by dehydration treatment. The amount of dehydration can be adjusted depending on the flavor and spiciness design, but dehydration to a hydrate rate of 20 to 60%, preferably 30 to 50%, is preferred from the viewpoint of the balance between flavor and spiciness. By carrying out a dehydration treatment, the hydrate rate can be increased.

[0050] In the present invention, it is preferable to depressurize the gas hydrate slurry before freezing. In this case, a depressurizing section having a depressurizing function may be provided between the separation section 16 and the freezing section 17. Alternatively, a depressurizing and freezing section having both a freezing function and a depressurizing function may be provided. In the depressurization treatment of the present invention, it is preferable to inject the gas hydrate slurry into a depressurization device having a filter at one end, and pressurize the gas hydrate slurry from the other end using a pressing means. In this case, the gas hydrate slurry is depressurized and dehydrated at the same time. Therefore, in the present invention, a dehydration / depressurization unit having a dehydration function and a depressurization function may be provided. Also, a dehydration / depressurization / freezing unit having a freezing function, a dehydration function, and a depressurization function may be provided. In an embodiment of the present invention, the freezing unit 17 is a dehydration / depressurization / freezing unit.

[0051] In the depressurization treatment, the raw material gas remaining in the gas hydrate slurry is separated. With the above configuration, the amount of raw material gas not used to form the gas hydrate contained in the gas hydrate-containing ice can be reduced, thereby improving the stability of the gas hydrate-containing ice.

[0052] The dehydration solution supply pipe 21 communicates with the freezing section 17 and the circulation path 111 . In the freezing section 17 , the dehydrated solution obtained by dehydrating the gas hydrate slurry is mixed with the raw solution supplied from the raw solution supply section 12 via the dehydrated solution supply pipe 21 . In this embodiment, the dehydrating solution supply pipe 21 is connected to the circulation path 111 upstream of the replenishment solution supply unit 19 of the circulation path 111 . In the present invention, the raw solution supply unit 12 and the freezing unit 17 may be connected by a pipe so that the dehydrated solution obtained by dehydration of the gas hydrate slurry is mixed with the raw solution in the raw solution tank 121. Specifically, the raw solution tank 121 may be connected to a dehydrated solution supply pipe 21.

[0053] The gas-liquid separation unit 18 separates the remaining raw material solution and the remaining raw material gas separated in the separation unit 16. As a method for separation, a method of heating the remaining raw material solution and the remaining raw material gas can be mentioned. Therefore, the gas-liquid separation unit 18 is preferably equipped with a heater. The gas-liquid separation unit 18 separates the remaining raw gas from the remaining raw solution, and supplies the separated remaining raw solution and remaining raw gas to the circulation line 116. The remaining raw solution then flows into the raw solution supply unit 12 via the circulation line 116 and can be reused for generating gas hydrate. Furthermore, gas-liquid separation unit 18 causes the remaining raw material gas separated from the remaining raw material solution to flow through circulation line 116 to remaining raw material gas supply pipe 22 connected to raw material solution supply unit 12. The remaining raw material gas is then supplied to gas-liquid mixing unit 14 through circulation line 112 and can be reused for producing gas hydrate.

[0054] The replenishment liquid supply unit 19 includes a replenishment liquid conduit 191, a check valve 192, and a liquid feed pump 193. The replenishment liquid conduit 191 connects, for example, a tap water pipe to the circulation path 11. By opening the check valve 192, tap water (replenishment liquid) flowing through the tap water pipe is guided to the circulation path 11 via the replenishment liquid conduit 191. Note that the replenishment liquid is not limited to tap water, and may be purified water. In this case, the replenishment liquid conduit 191 connects a tank that stores purified water to the circulation path 11. In the present invention, the replenishment liquid conduit 191 may be connected to the raw solution supply unit 12 by piping so as to supply the replenishment liquid into the raw solution tank 121. Specifically, the raw solution tank 121 and the replenishment liquid conduit 191 may be in communication with each other.

[0055] The replenishment liquid supply unit 19 supplies water to the circulation path 111 to compensate for the decrease in water due to the generation of gas hydrate. Specifically, the replenishment liquid supply unit 19 and the circulation path 111 are connected, and water is added to the raw solution supplied from the raw solution supply unit 12, or to a mixture of the raw solution supplied from the raw solution supply unit 12 and the dehydrated solution produced by the dehydration treatment.

[0056] If the raw solution contains an additive, the concentration of the raw solution in the raw solution supply unit 12 into which the remaining raw solution flows increases due to continuous operation of the manufacturing apparatus 1. Furthermore, the concentration may change due to mixing with the dehydration treatment solution. To maintain a constant concentration of the raw solution supplied from the raw solution supply unit 12 during continuous operation of the manufacturing apparatus 1, water can be supplied from the replenishment liquid supply unit 19. In this case, the replenishment liquid supply unit 19 functions as a concentration adjustment unit for adjusting the concentration of the raw solution mixed with the remaining raw solution. Here, the concentration adjustment unit may have a function for measuring the concentration of the raw solution. Alternatively, a Brix meter may be installed upstream of the replenishment liquid supply unit 19 in the circulation path 111, and water may be added when the Brix exceeds a predetermined upper limit.

[0057] For example, the replenishment liquid supply unit 19 calculates the amount of water lost from the gas hydrate-containing ice produced in the freezing unit 17 due to the production of gas hydrate, and controls the opening and closing of the check valve 192 so as to supply the lost amount of water to the circulation path 111. In another embodiment, the amount of water required to maintain a constant concentration of the raw material solution is calculated in advance, and the opening and closing of the check valve 192 is controlled so as to supply the required amount of water to the circulation path 111.

[0058] Further, the replenishment liquid supply unit 19 can also guide the raw material solution to the circulation path 111. In this case, the replenishment liquid guide pipe 191 connects the circulation path 111 to a tank that stores the raw material solution.

[0059] When the raw solution is introduced into circulation path 111, replenishment liquid supply unit 19 calculates the amount of raw solution used to produce gas hydrate-containing ice by, for example, measuring the water level from the pressure difference between the raw gas and raw solution in raw solution tank 121 with a level meter installed in raw solution tank 121, and controls the opening and closing of check valve 192 so as to supply the raw solution to make up the decrease in amount to circulation path 111. In another embodiment, the amount of raw solution used to produce the gas hydrate-containing ice is calculated, and the opening and closing of check valve 192 is controlled so as to supply the raw solution to make up the decrease in amount to circulation path 111. As a calculation method, for example, the amount of gas hydrate produced can be determined from the amount of raw gas supplied from raw gas supply unit 13, and the amount of raw solution used to produce the gas hydrate-containing ice can be determined.

[0060] Next, an outline of a method for producing gas hydrate-containing ice according to one embodiment of the present invention will be described with reference to Fig. 3. Specifically, the method for producing gas hydrate-containing ice using a production apparatus 1 will be described. Fig. 3 is a flowchart illustrating the flow of a method for producing gas hydrate-containing ice according to one embodiment of the present invention. The production apparatus 1 has the above-described configuration. Furthermore, the description of the production apparatus 1 can be used to refer to preferred embodiments of each configuration.

[0061] First, a raw material gas is mixed with a raw material solution in the gas-liquid mixing unit 14 (S11; gas-liquid mixing step). The raw material solution is supplied from the raw material solution supply unit 12 via circulation paths 111 and 112, and the raw material gas is supplied from the raw material gas supply unit 13 to the circulation path 112.

[0062] Next, gas hydrate is produced from the mixture of the raw material solution and the raw material gas (S12: gas hydrate production step). The gas hydrate can be produced in a gas hydrate production unit 15.

[0063] Then, a gas hydrate slurry containing the gas hydrate and a portion of the raw material solution is separated from the remaining raw material solution (S13: solid-liquid separation step). The gas hydrate slurry and the remaining raw material solution can be separated in separation section 16. In the separation section 16, the remaining raw material gas may be separated together with the remaining raw material solution.

[0064] Finally, the gas hydrate slurry is frozen to produce gas hydrate-containing ice (S14: freezing step). The gas hydrate-containing ice can be produced in freezing section 17.

[0065] In the present invention, it is preferable to provide a dehydration step of dehydrating the gas hydrate slurry before the freezing step. By carrying out the dehydration step, the gas hydrate content can be increased. The dehydration step is carried out in a dehydration section.

[0066] In the present invention, it is preferable to provide a depressurization step of depressurizing the gas hydrate slurry before the freezing step. The depressurization step is carried out in a depressurization section.

[0067] When producing gas hydrate-containing ice by a batch method, a gas hydrate slurry containing gas hydrate and most of the raw material solution is frozen directly in a gas hydrate production vessel to produce gas hydrate-containing ice. In this case, due to gravity, the gas hydrate-containing ice is produced with a high hydrate content in the lower part and a low hydrate content in the upper part. In other words, the gas hydrate distribution in the gas hydrate-containing ice becomes uneven, resulting in unstable quality. In the present invention, gas hydrate-containing ice is produced by freezing a gas hydrate slurry containing the gas hydrate and a portion of the raw material solution, and as a result, there is no bias in the distribution of gas hydrate in the gas hydrate-containing ice.

[0068] A method for producing gas hydrate-containing ice by repeating steps S11 to S14 will be described below.

[0069] In the method for producing gas hydrate-containing ice in which steps S11 to S14 are repeatedly performed, the remaining raw solution can be used in the gas-liquid mixing step. In this case, the remaining raw solution flows into raw solution supply unit 12 after the solid-liquid separation step and is mixed with the raw solution in raw solution supply unit 12.

[0070] It is also preferable to separate the remaining raw material solution from the remaining raw material gas contained in the remaining raw material solution (gas-liquid separation step). The remaining raw material solution and the remaining raw material gas contained in the remaining raw material solution can be separated in gas-liquid separation unit 18. Preferably, the remaining raw material solution, which is separated from the remaining raw material gas contained in the remaining raw material solution, is used in the gas-liquid mixing step.

[0071] In addition, a dehydrated solution produced by dehydration of a gas hydrate slurry can also be used in the gas-liquid mixing step. In this case, the dehydrated solution may flow into raw solution supply unit 12 via dehydrated solution supply pipe 21, or may be mixed with the raw solution supplied from raw solution supply unit 12 in circulation path 111.

[0072] The method for producing gas hydrate-containing ice in which S11 to S14 are repeatedly performed preferably includes a concentration adjustment step of adjusting the concentration of the raw solution mixed with the remaining raw solution and / or the dehydrated solution. The raw solution mixed with the remaining raw solution and / or the dehydrated solution has a reduced amount of water contained in the raw solution due to the generation of gas hydrate, and therefore, it is considered that the concentration of the raw solution changes each time S11 to S14 are repeated.

[0073] The concentration of the raw material solution mixed with the remaining raw material solution and / or the dehydration treatment solution can be adjusted by the replenishment liquid supply unit 19.

[0074] In the method for producing gas hydrate-containing ice in which S11 to S14 are repeatedly performed, the remaining raw material gas separated in the gas-liquid separation section 18 can be used in the gas-liquid mixing step.

[0075] According to the present invention, when continuously producing gas hydrate-containing ice, the concentration of the raw material solution can be kept constant, there is no bias in the distribution of gas hydrate, and there is no variation in the taste of the gas hydrate-containing ice.

[0076] In the present invention, it is preferable to further include an ice crushing step of crushing the gas hydrate-containing ice produced in the freezing step to obtain a plurality of small pieces. According to the present invention, there is no bias in the distribution of gas hydrate among a plurality of small chunks of gas hydrate-containing ice, and there is no variation in the taste of the gas hydrate-containing ice. [Industrial Applicability]

[0077] According to the present invention, it is possible to produce gas hydrate-containing ice with little bias in the distribution of gas hydrate and with little variation in taste. [Explanation of symbols]

[0078] 1 Manufacturing equipment 11 Circulation path 12 Raw material solution supply section 121 Raw material solution tank 13 Raw material gas supply section 131 Raw gas tank 132 Raw material gas supply pipe 133 Mass Flow Controller 14 Gas-liquid mixing section 15 Gas hydrate generation section 16 Separation section 161 Storage Tank 162 Valve 163 Baffle plate 17 Freezing section 18 Gas-liquid separation section 19 Replenishment fluid supply section 191 Replenishment liquid water pipe 192 Check valve 193 Liquid transfer pump 20 Circulation Pump 21 Dehydration treatment solution supply pipe 22 Residual raw gas supply pipe 23a Baffle plate 23b Baffle plate 23c Baffle plate

Claims

1. a circulation path through which the raw material solution circulates; a gas-liquid mixing section provided in the circulation path for mixing the raw material solution with a raw material gas; a gas hydrate production section provided downstream of the gas-liquid mixing section in the circulation path, which produces gas hydrate from a mixed liquid of the raw material solution and the raw material gas; a freezing unit that freezes a gas hydrate slurry containing the gas hydrate and a portion of the raw material solution to produce gas hydrate-containing ice; An apparatus for producing gas hydrate-containing ice, comprising:

2. 2. The apparatus for producing gas hydrate-containing ice according to claim 1, further comprising a separation section between the gas hydrate production section and the freezing section, the separation section separating the gas hydrate slurry from the remaining raw material solution.

3. 3. The apparatus for producing gas hydrate-containing ice according to claim 2, further comprising a dehydration unit for dehydrating the gas hydrate slurry.

4. 4. The apparatus for producing gas hydrate-containing ice according to claim 3, wherein the separation section separates the gas hydrate slurry from the residual raw material solution containing the residual raw material gas.

5. 5. The apparatus for producing gas hydrate-containing ice according to claim 4, further comprising a gas-liquid separator that separates the remaining raw solution containing the remaining raw gas into the remaining raw solution and the remaining raw gas.

6. 6. The apparatus for producing gas hydrate-containing ice according to claim 1, further comprising a concentration adjusting unit for adjusting the concentration of the raw material solution.

7. 6. The apparatus for producing gas hydrate-containing ice according to claim 1, wherein the separation section is provided with a baffle plate.

8. a gas-liquid mixing step of mixing a raw material gas with a raw material solution; a gas hydrate generation step of generating a gas hydrate from a mixed liquid of the raw material solution and the raw material gas; a freezing step of freezing a gas hydrate slurry containing the gas hydrate and a portion of the raw material solution to produce gas hydrate-containing ice; A method for producing gas hydrate-containing ice, comprising:

9. 9. The method for producing gas hydrate-containing ice according to claim 8, wherein the gas-liquid mixing step, the gas hydrate generating step, and the freezing step are repeatedly performed, The method for producing gas hydrate-containing ice includes a solid-liquid separation step of separating the gas hydrate slurry from the remaining raw material solution, and a dehydration step of dehydrating the gas hydrate slurry.

10. the remaining raw material solution is mixed with the raw material solution and used in the gas-liquid mixing step; The method for producing gas hydrate-containing ice according to claim 9 , further comprising a concentration adjusting step of adjusting the concentration of the raw material solution mixed with the remaining raw material solution.

11. 11. The method for producing gas hydrate-containing ice according to claim 8, wherein the raw material solution is an aqueous solution containing one or more components selected from the group consisting of flavorings, sweeteners, acidulants, emulsifiers, stabilizers, salts, and amino acids.

12. 11. The method for producing gas hydrate-containing ice according to claim 8, further comprising a gas-liquid separation step of separating the remaining raw solution from the remaining raw gas, and using the remaining raw gas in the gas-liquid mixing step.

13. 11. The method for producing gas hydrate-containing ice according to claim 8, further comprising an ice crushing step of crushing the gas hydrate-containing ice produced in the freezing step to obtain a plurality of small pieces.

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