A freeze concentration method

Abstract

The present invention belongs to the technical field of freeze concentration, and specifically relates to a freeze concentration method, which utilizes the negative correlation between melting point and solute concentration, freezes a dilute solution into a solid (ice body) or a solid-liquid mixture (ice body + concentrated solution), sets a heat source at a specific position of the solid or solid-liquid mixture for heating, and achieves freeze concentration of the dilute solution through dissolution and separation. The method improves the efficiency of freeze concentration and separation and purification, is simple to operate, and is convenient for application in the fields of food, cosmetics, biomedicine, environmental protection treatment, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of freeze concentration, and in particular relates to a freeze concentration method. Background Art

[0002] The freeze concentration method in the prior art is a concentration technology that utilizes the solid-liquid phase relationship between a dilute solution and ice below the freezing point. There are two main methods: suspended crystallization freeze concentration and progressive freeze concentration. The principle of the suspended crystallization freeze concentration method is that when a dilute solution is frozen, the free small ice crystals suspended in the liquid are continuously removed to increase the liquid concentration. The principle of the progressive freeze concentration method is that when a dilute solution is frozen, as the ice layer is generated and grows on the cooling surface, the solute near the solid-liquid interface is removed to the liquid phase side, resulting in a concentration method in which the mass concentration of the solute in the liquid phase gradually increases. The existing freeze concentration method has a complex equipment structure, high equipment cost and production cost, and low efficiency.

[0003] When ice melts naturally, a relatively high concentration solution will be dissolved first. By taking advantage of this phenomenon, the concentration of the dilute solution can be increased by freezing the solution into a solid state and then dissolving it again. This is a freeze concentration method that uses the natural dissolution of ice. However, although this method is simple to operate, it is very time-consuming and has low work efficiency. This method is rarely used in large-scale industrial freeze concentration.

[0004] In addition, some public documents have devices and methods for heating and dissolving frozen materials to produce concentrated solutions, but due to defects in the methods, the effect and efficiency of freeze concentration are not high. For example, in the device and method disclosed in the patent application with publication number JP2004351383A, steam and hot air are used to heat and dissolve frozen materials. This method does not take into account that the frozen material formed by freezing by this method, its solid surface and internal structure will affect the separation effect and efficiency of its solution dissolved by heat, and the ice layer formed on the surface of the frozen material and the area adjacent to the container wall will be denser than the ice body inside the frozen material, and the solute content of the ice layer will be lower. The heat transfer direction of the heating method adopted by this method is that heat is transferred from the low-solubility ice layer to the frozen material. Such heat transfer will obviously seriously affect the effect and efficiency of the frozen material being dissolved by heat, thereby affecting the effect and efficiency of freeze concentration, which will affect the efficiency and promotion of its industrial production. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the main purpose of the present invention is to propose a freeze concentration method, which utilizes the negative correlation between melting point and solute concentration, freezes the dilute solution into a solid (ice body) or a solid-liquid mixture (ice body + concentrated solution), and sets a heat source at a specific position of the solid or solid-liquid mixture to heat and achieve dissolution and separation, thereby achieving freeze concentration of the dilute solution and improving the efficiency of freeze concentration.

[0006] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0007] A freeze concentration method comprises the following steps:

[0008] S1. Freezing the dilute solution to obtain a solid or a solid-liquid mixture;

[0009] S2, setting a heat source at a specific position of the solid or solid-liquid mixture for heating, and taking out the solution in sections to obtain solutions of different concentrations;

[0010] S3. The solution that meets the target concentration is transferred to the next stage (for standby); for the solution that does not meet the target concentration, steps S1-S2 are repeated to continue to increase the solution concentration.

[0011] As a preferred embodiment of the freeze concentration method of the present invention, in step S2, the specific orientation is a description of a directional region: from the cooling surface when the dilute solution is frozen into a solid or a solid-liquid mixture, the specific orientation region is the region in the direction of the solid or solid-liquid mixture from the cooling surface away from the cooling surface (except for the solid layer with low solute content adjacent to the cooling surface). This region can be inside or outside the solid or solid-liquid mixture (related to the position of the cooling surface).

[0012] As a preferred embodiment of the freeze concentration method described in the present invention, in step S2, the heat source is set in a specific orientation, and the heat transfer direction of the heat source is characterized in that when transferring heat to the solid or solid-liquid mixture, the heat is avoided as much as possible from being transferred to the solid layer with low solute content in the solid or solid-liquid mixture first.

[0013] As a preferred embodiment of the freeze concentration method of the present invention, in step S2, the heat source is arranged at a specific position in the following manner:

[0014] Inserting a heat source into the solid or solid-liquid mixture obtained by freezing;

[0015] Or process (e.g. drill out, cut out) the location where the heat source needs to be set on the solid or solid-liquid mixture, and then place (insert) the heat source;

[0016] Or preset the heat source where you need to set the heat source during the freezing process.

[0017] As a preferred embodiment of the freeze concentration method of the present invention, in step S2, the shape of the heat source includes: point, line (column), surface (plate), and sphere.

[0018] As a preferred embodiment of the freeze concentration method described in the present invention, in step S1, when the heating temperature is lower than the freezing point or the eutectic point, a guide channel can be set on the solid or solid-liquid mixture obtained by freezing, which can improve the effects of freeze concentration and separation and purification.

[0019] As a preferred embodiment of the freeze concentration method described in the present invention, in said step S1, a plurality of flow guide channels are directly processed on the solid or solid-liquid mixture obtained by freezing; the processing methods include drilling, piercing, inserting, piercing and the like.

[0020] As a preferred embodiment of the freeze concentration method of the present invention, in the step S1, the flow guide channel is provided by inserting a flow guide device into the solid or solid-liquid mixture obtained by freezing.

[0021] As a preferred embodiment of the freeze concentration method of the present invention, in step S1, the diversion channel is provided by crushing the solid layer in the outflow direction of the solution obtained after the solid or solid-liquid mixture is heated.

[0022] As a preferred embodiment of the freeze concentration method of the present invention, in step S1, the diversion channel is provided by presetting a diversion channel or a diversion device with a diversion function during the freezing process.

[0023] As a preferred embodiment of the freeze concentration method of the present invention, in step S2, after the solid or solid-liquid mixture is heated, the solution is separated and discharged in a manner of natural outflow, negative pressure extraction or centrifugal separation.

[0024] To solve the above technical problem, according to another aspect of the present invention, the present invention provides the following technical solution:

[0025] An application of the above freeze concentration method in the fields of food, cosmetics, biomedicine, environmental protection treatment, etc.

[0026] The freeze concentration method is applied in the fields of milk, wine, juice, coffee, tea, beverages, soy milk, chemical liquid, Chinese herbal liquid, plant extract, seawater desalination, wastewater treatment, etc.

[0027] An application of the freeze concentration method in the field of freeze concentration and separation and purification of heat-sensitive raw materials.

[0028] The freeze concentration method is applied in the freeze concentration and separation and purification fields of milk, wine, juice, coffee, tea, beverages, soybean milk, soy milk, chemical liquid, Chinese herbal liquid, plant extract, seawater desalination, wastewater treatment, etc.

[0029] The beneficial effects of the present invention are as follows:

[0030] The present invention proposes a freeze concentration method, which utilizes the negative correlation between melting point and solute concentration, freezes a dilute solution into a solid (ice body) or a solid-liquid mixture (ice body + concentrated solution), sets a heat source at a specific position of the solid or solid-liquid mixture for heating, and achieves freeze concentration of the dilute solution through dissolution and separation. The method improves the efficiency of freeze concentration and separation and purification, is simple to operate, and is convenient for application in the fields of food, cosmetics, biomedicine, environmental protection treatment, etc. DETAILED DESCRIPTION

[0031] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The present invention proposes a freeze concentration method, which breaks the traditional freeze concentration thinking, improves the efficiency of freeze concentration and separation and purification, is simple to operate, and is convenient for application in the fields of food, cosmetics, biomedicine, environmental protection treatment, etc.

[0033] In order to express the concept of specific orientation more clearly, the following two examples are given:

[0034] (1) A cylindrical freezing device: a dilute solution is frozen into a solid or a solid-liquid mixture in this device. When freezing a dilute solution, the refrigerant is located outside the dilute solution container in the device, and the cooling surface is the container wall close to the refrigerant. When setting a heat source, it should be set in a specific orientation area, which is the area in the direction of the solid or solid-liquid mixture leaving the cooling surface. In this device, the central axis of the solid or solid-liquid mixture and the surrounding area are within the scope of this area: that is, the central axis of the ice body and the surrounding area, except for the solid layer with low solute content formed near the cooling surface, are all in compliance. One heat source (heating rod) or multiple heat sources (multiple heat source rods) can be set in this area.

[0035] (2) A cylindrical freezing device: In this device, the refrigerant passes through the device from the central axis area through a sealed pipe. When freezing a dilute solution into a solid or a solid-liquid mixture, the cooling surface is the outer wall of the refrigerant tube. When setting the heat source, it should be set in a specific orientation area, which is the area in the direction of the solid or solid-liquid mixture leaving the cooling surface, that is, the heat source can be set in the ice body near the outer wall of the container, or it can be set outside the outer wall of the container. The solid layer with low solute content formed in the solid (ice body) near the outer wall (cooling surface) of the refrigerant pipe is not within the specific orientation range.

[0036] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0037] Example 1

[0038] A freeze concentration method for thorny grape juice, taking 56L thorny grape juice with a refractive index of 14.3% and putting it into a cylindrical container, freezing it into a cylindrical solid at -18°C in a freezer, setting a linear (or columnar) heat source at the axis of the cylindrical solid and its surrounding area (i.e., a specific orientation) for heating, the heat source temperature is 45°C, and the temperature of the outflowing solution is kept below 0°C during the melting of the ice body. Two target concentrations are set for recording, the first target concentration: the refractive index is 30%, and the second target concentration: the refractive index is 18%. The dissolved outflowing liquid is collected, and the specific situation is shown in Table 1.

[0039] Table 1 Details of the segmented solution in Example 1

[0040]

[0041] Example 2

[0042] The difference from Example 1 is that the heat source temperature is 65°C.

[0043] The dissolved liquid was collected, and the specific situation is shown in Table 2.

[0044] Table 2 Details of the segmented solution in Example 2

[0045]

[0046] Example 3

[0047] The difference from Example 2 is that the amount of thorn grape juice is 25L.

[0048] The dissolved liquid was collected, and the specific situation is shown in Table 3.

[0049] Table 3 Details of the segmented solution in Example 3

[0050]

[0051] Comparative Example 1

[0052] The difference from Example 1 is that the heat source is not set in a specific direction, and a natural dissolution method is adopted.

[0053] The dissolved liquid was collected, and the specific situation is shown in Table 4.

[0054] Table 4 Details of the segmented solution of Comparative Example 1

[0055]

[0056] Example 4

[0057] A freeze concentration method for thorny grape wine, wherein 55L of thorny grape wine with an alcohol content of 14.8%vol is put into a cylindrical container and frozen into a cylindrical solid-liquid mixture at -18°C in a freezer, at which the surface of the original liquid of the thorny grape wine and the thorny grape wine adjacent to each peripheral surface of the container are frozen into an ice layer, and ice crystals grown from the ice layer are also filled inside it, which encloses liquid that has not been frozen into a solid. The container is moved out of the freezer, and a linear (or columnar) heat source is set at a specific position (in this embodiment, the central axis of the container and the area around it are the specific position area for setting the heat source) for heating and dissolving, and the temperature of the heat source is 35°C. During the dissolution process, the temperature of the outflowing solution is kept below 0°C. The dissolved outflowing liquid is collected, and the specific situation is shown in Table 5.

[0058] Table 5 Details of the segmented solution of Example 4

[0059]

[0060] In the above embodiments, Example 1 (thorny grape juice), Example 2 (thorny grape juice), Example 3 (thorny grape juice), and Comparative Example 1 (thorny grape juice) are all frozen into solids; Example 4 (thorny grape wine) is frozen into a solid-liquid mixture. After freezing, heat sources are set at their specific positions to transfer heat to them for dissolution and separation. The dissolution conditions are recorded in Table 1, Table 2, Table 3, Table 4, and Table 5 respectively.

[0061] It can be seen from the above embodiments and comparative examples that:

[0062] The volumes of the first target concentration (refractive sugar content of 30%) of the thorn grape juice obtained in Comparative Example 1 and Examples 1-2 are 2.5L, 14.1L, and 13.2L, respectively, accounting for 4.46%, 25.18%, and 23.57% of the original solution volume, respectively. It can be seen that the concentration effect of the method of the present invention is compared with the natural dissolution method (Comparative Example 1, the existing "ice slide" technology), and the advantages in the high concentration range are very obvious: the volume of the first target concentration range solution obtained in Example 1 of the present invention is 5.64 times that of Comparative Example 1 (natural dissolution method).

[0063] The dissolution and separation rates (L / h) of the thorny grape juice of the first target concentration (refractive sugar content of 30%) obtained in Comparative Example 1 and Examples 1-2 are 0.5 L / h, 1.47 L / h, and 1.65 L / h, respectively. The dissolution and separation rate of the ice body in the first target concentration range of Example 2 of the present invention is 3.3 times that of Comparative Example 1 (natural dissolution method).

[0064] The volume proportions of the thorn grape juice with a refractive index of less than 5% obtained in Comparative Example 1 and Examples 1-2 are 34.43%, 49.46% and 49.64% respectively. It can be seen that the concentration and separation effect of the present invention is higher than that of the natural dissolution method.

[0065] It can be seen from Examples 1-2 that when the volume of the original liquid is the same, the temperature of the heat source increases, and the dissolution and separation speed of the ice body is accelerated.

[0066] It can be seen from Examples 2-3 that when the temperature of the heat source is constant, the smaller the volume of the ice body is, the faster the melting and separation speed of the ice body is.

[0067] As can be seen from Example 4, the thorny wine is frozen into a solid-liquid mixture at -18°C (the surface is covered with ice) and then removed from the freezer. Then, holes (the holes are also channels for solution separation and outflow) that can be installed with linear (or columnar) heat sources are drilled in the central axis of the container and the surrounding area (the area is the specific orientation area where the heat source is set), so that the thorny wine concentrated solution that is not frozen into a solid and is wrapped by the solid can be separated and flowed out from the hole channel. For example, the first section of the solution in Table 5 is a thorny wine with an alcohol content of 26%vol, accounting for 49.45% by volume. Compared with the original thorny wine with an alcohol content of 14.8%vol, the alcohol content is increased by 75.68%. After separating the first section of the solution, a linear (or columnar) heat source is inserted into the hole (located in the specific orientation area) to transfer heat to the separated solid, and the solution is retained in sections. From the second section of the solution, the solid is dissolved and separated. The second section of the solution is a thorny wine with an alcohol content of 6.98%vol, accounting for 13.20% by volume. The fourth stage solution is thorn wine with an alcohol content of 0.45% vol, accounting for 17.75% by volume. Therefore, when the thorn wine is frozen into a solid-liquid mixture and heated and dissolved, the effect and efficiency of increasing the alcohol content of the fermented wine are better than those of the traditional method.

[0068] The present invention utilizes the negative correlation between the melting point and the solute concentration in the solution, freezes the dilute solution into a solid (ice body) or a solid-liquid mixture (ice body + concentrated solution), sets a heat source at a specific position of the solid or solid-liquid mixture for heating, and realizes freeze concentration of the dilute solution through dissolution and separation. The method improves the efficiency of freeze concentration and separation and purification, is simple to operate, and is convenient for application in the fields of food, cosmetics, biomedicine, environmental protection treatment, etc.

[0069] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A freeze concentration method, characterized in that: The steps include: S1. Freezing the dilute solution to obtain a solid or a solid-liquid mixture; S2, setting a heat source at a specific position of the solid or solid-liquid mixture for heating, and taking out the solution in sections to obtain solutions of different concentrations; The specific orientation is a description of a directional area: from the cooling surface when the dilute solution is frozen into a solid or a solid-liquid mixture, the specific orientation area is the area in the direction of the solid or solid-liquid mixture leaving the cooling surface; S3. The solution that meets the target concentration is transferred to the next stage; the solution that does not meet the target concentration repeats steps S1-S2 to continue to increase the solution concentration.

2. The freeze concentration method according to claim 1, characterized in that In step S2, the region is inside or outside the solid or solid-liquid mixture.

3. The freeze concentration method according to claim 1, characterized in that In step S2, the heat source is set at a specific position, and the heat transfer direction is characterized by: when transferring heat to the solid or solid-liquid mixture, the heat is prevented from being first transferred to the solid layer with low solute content in the solid or solid-liquid mixture.

4. The freeze concentration method according to claim 1, characterized in that In step S2, the method of setting the heat source at a specific position is: Inserting a heat source into the solid or solid-liquid mixture obtained by freezing; Alternatively, the location where the heat source needs to be set is processed on the solid or solid-liquid mixture, and then the heat source is placed; Or preset the heat source where you need to set the heat source during the freezing process.

5. The freeze concentration method according to claim 1, characterized in that In the step S2, the shape of the heat source includes: point, line, surface, and sphere.

6. The freeze concentration method according to claim 1, characterized in that: In step S2, after the solid or solid-liquid mixture is heated, the solution is separated and discharged in the following ways: natural outflow, negative pressure extraction or centrifugal separation.

7. Application of the freeze concentration method according to any one of claims 1 to 6 in the fields of food, cosmetics, biomedicine, and environmental protection treatment.

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