Freeze concentration method

Abstract

The invention relates to a freeze concentration method. A dilute solution is frozen into a solid state (hereinafter referred to as an ice body) or a solid-liquid mixed state (ice body and concentrated solution), a flow guide channel is arranged, heat is transferred, and the concentration target is achieved through dissolution. The flow guide channel is arranged, so that the solution in the ice body (or the ice body and the concentrated solution) is separated and flows out more easily, and the concentration of the flowing-out solution is gradually reduced from high to low. And according to the requirement of the target concentration, the solutions are retained in sections, so that the solutions with different concentrations are obtained. And transferring the solution meeting the target concentration to the next link for storage (utilization). Solutions which do not conform to the target concentration can be repeatedly frozen and concentrated through the method, and the concentration of the solutions continues to be increased. The method is simple to operate and high in efficiency, can be operated at normal pressure and low temperature, and is suitable for freeze concentration, separation and purification of heat-sensitive raw materials. For example, the device is used for freezing concentration and separation purification of milk, wine, fruit juice, coffee, tea beverage, soymilk, chemical (original) liquid medicine, Chinese herbal medicine liquid and the like.

Description

TECHNICAL FIELD The present application belongs to the technical field of freeze concentration, and particularly relates to a freeze concentration method. BACKGROUND

[0001] The existing freeze concentration method is a concentration technology realized by using the solid-liquid correlation of dilute solution and ice below the freezing point. There are mainly two ways: the suspension crystallization freeze concentration method and the gradual freeze concentration method. The principle of the suspension crystallization freeze concentration method is that when the dilute solution is frozen, the free small ice crystals suspended in the liquid are continuously removed, so that the concentration of the liquid is increased. The principle of the gradual freeze concentration method is that when the dilute solution is frozen, with the generation and growth of the ice layer on the cooling surface, the solute near the solid-liquid interface is removed to the liquid phase side, resulting in the gradual increase of the mass concentration of the solute in the liquid phase. The existing freeze concentration method has a complex device structure, high equipment cost, high production cost, and low efficiency, and is less used in the application of fruit juice concentration.

[0002] When the ice body is naturally dissolved, the solution with relatively high concentration will be dissolved first. By freezing the solution into solid state multiple times and then dissolving it, the concentration of the dilute solution can be increased, which is a freeze concentration method through the natural dissolution of ice body. However, this method is simple to operate, but it takes a very long time and has low working efficiency, so it is rarely used in industrial freeze concentration. In addition, in some materials, there are devices and methods for heating and dissolving frozen materials to produce concentrated solutions, but because of the defects in the method, the effect and efficiency of freeze concentration are restricted. For example, in the device and method of publication number JP2004351383A, steam and hot gas are used to heat the frozen materials. However, in this device and method, the influence of the surface and internal solid state structure of the frozen materials and the separation and outflow of the concentrated solution is not considered, thereby restricting the effect and efficiency of freeze concentration of the device and method, and affecting the efficiency and popularization of industrial production.

[0003] The present application method utilizes the negative correlation between melting point and concentration, as well as the structure characteristics of the solid state (or solid-liquid mixed state) formed when the solution is frozen into solid state or solid-liquid mixed state, and through the setting of the flow channel and the transfer of heat for dissolution and separation, the freeze concentration of the dilute solution is realized, and the efficiency of freeze concentration and separation and purification is improved. The present application method has simple equipment and easy operation, and can realize large-scale industrial production. SUMMARY The present invention relates to a method of freeze concentration. Dilute solution is frozen into solid state (hereinafter referred to as ice body), or solid-liquid mixed state (ice body + concentrated solution), and a flow channel is set up in the ice body (or ice body + concentrated solution) to transfer heat and achieve the goal of concentration by dissolution. The flow channel is set up to make the solution in the ice body (or ice body + concentrated solution) more easily separated and flow out, and the concentration of the outflowing solution gradually decreases from high to low. According to the needs of the target concentration, the solution is segmented and retained, and different concentrations of solution are obtained. The solution that meets the target concentration is transferred to the next link for storage (use). The solution that does not meet the target concentration can be repeatedly frozen and concentrated by the method to continue to improve the concentration of the solution. The method is simple to operate, efficient, and can be operated at normal pressure and low temperature, and is suitable for freeze concentration and separation and purification of heat-sensitive and sensitive raw materials. For example, it is used for freeze concentration and separation and purification of milk, wine, fruit juice, coffee, tea beverage, soy milk, chemical (original) liquid medicine, Chinese herbal medicine liquid, etc.

[0004] Case: Take 2 parts of thorny grape wine (alcohol content 23.56 degrees), each with a volume of 6000 ml, and put them into cylindrical containers, then send them to the freezer (or refrigeration warehouse) to freeze into ice bodies at a temperature of minus 40 degrees Celsius. Two ice bodies (called ice body A and ice body B, respectively) are heated and dissolved under the following different conditions.

[0005] A ice body: no flow channel is set up, and the ice body is heated from the outside, with a dissolution temperature of 30 degrees Celsius (referring to the temperature of the heat source, the same below).

[0006] B ice body: a flow channel is set up in the ice body, and the ice body is heated from the outside, with a dissolution temperature of 30 degrees Celsius (referring to the temperature of the heat source, the same below). In this case, the flow channel is set up by piercing 5 flow holes in the ice body.

[0007] During the whole heating and dissolution process, the temperature of the separated and outflowing solution is lower than 0 degrees Celsius. The specific dissolution conditions are shown in Table 1 and Table 2 (the external heating temperature is the temperature of the heat source).

[0008] From the recorded data in Table 1 and Table 2, it can be found that: The dissolution conditions of ice body A (original wine alcohol content 23.56 degrees) when heated from the outside without setting up a flow channel and with a dissolution temperature of 30 degrees Celsius are as follows: the alcohol content of the first segment of solution is 26.68 degrees (V%), and the volume ratio is 22.8%. The alcohol content of the second segment of solution is 28.54 degrees (V%), and the volume ratio is 48.4%. The alcohol content of the third segment of solution is 16.64 degrees (V%), and the volume is 16%. The alcohol content of the fourth segment of solution is 3.38 degrees (V%), and the volume is 12.5% Ice body B (original alcohol content 23.56%), with a flow channel inside, is heated from the outside. The dissolution at 30°C is as follows: The first solution has an alcohol content of 34.5% (V%) and a volume percentage of 22.3%. The second solution has an alcohol content of 27.29% (V%) and a volume percentage of 48.4%. The third solution has an alcohol content of 11.27% (V%) and a volume percentage of 14.6%. The fourth solution has an alcohol content of 1.46% (V%) and a volume percentage of 14.16%.

[0009] Comparison of dissolution and concentration with and without flow channels: First stage of solution collection: Without a flow channel, the resulting liquor volume is 22%, and the alcohol content is 26.68%. With a flow channel, the resulting liquor volume is 22%, and the alcohol content is 34.5%. It is evident that the flow channel significantly increases the alcohol content, demonstrating a remarkable effect of freeze-concentration.

[0010] The second section of collected solutions had the same volume and little difference in alcohol content.

[0011] The third section of the collected solution: Without a flow channel, the alcohol content of 16% (by volume) of the resulting liquid is 16.64 degrees. With a flow channel, the alcohol content of 14.6% (by volume) of the resulting liquid is 11.27 degrees. It is evident that with a flow channel, the solute (alcohol) in this section of the solution is significantly less than when no flow channel is present.

[0012] The fourth stage of solution collection: Without a flow channel, the alcohol content of 12.5% ​​(by volume) of the resulting liquid is 3.38%. With a flow channel, the alcohol content of 14.16% (by volume) of the resulting liquid is only 1.46%. It is evident that with a flow channel, the freeze-concentration effect is significantly better than without one.

[0013] In summary, by setting up flow channels within the ice body (or ice body + concentrated solution) after freezing a dilute solution into ice (or ice body + concentrated solution) and transferring heat to facilitate dissolution, the effect and efficiency of freeze concentration can be significantly improved.

[0014] The above embodiments are merely preferred examples and are not intended to limit the present invention. Various modifications and alterations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the protection of the present invention.

Claims

1. A freeze-concentration method involves freezing a dilute solution into a solid state (hereinafter referred to as ice) or a solid-liquid mixture (ice + concentrated solution), and setting up a flow channel to transfer heat to achieve concentration through dissolution. The flow channel facilitates the separation and outflow of the solution from the ice (or ice + concentrated solution), with the concentration of the outflowing solution gradually decreasing. Depending on the target concentration, solutions are collected in stages to obtain solutions of different concentrations. Solutions meeting the target concentration are transferred to the next stage for preservation (utilization). Solutions not meeting the target concentration can be repeatedly freeze-concentrated using this method to further increase the solution concentration. This method is simple to operate, highly efficient, and can be performed at normal pressure and low temperature, making it suitable for the freeze-concentration and separation purification of heat-sensitive raw materials.

2. The freeze-concentration method according to claim 1, characterized in that: Dilute solutions can be frozen into solids (hereinafter referred to as ice) or solid-liquid mixtures (ice + concentrated solution) in cold storage, refrigerators (freezers) or other refrigeration equipment.

3. The freeze-concentration method according to claim 1, characterized in that: Methods for setting up flow channels for ice (or ice + concentrated solution) include (but are not limited to) the following methods: setting one or more flow channels in the ice (or ice + concentrated solution) (e.g., drilling, piercing, punching, or other mechanical means); inserting flow channels (or flow devices) into the ice (or ice + concentrated solution); breaking up the ice layer on the surface of the ice (or ice + concentrated solution) in the direction of solution outflow (the thickness to be broken is related to the surface ice layer structure); and pre-setting flow channels (or devices with flow guiding functions) in the freezing chamber (or container) of a freezing concentration device.

4. The freeze-concentration method according to claim 1, characterized in that: A flow channel is designed to facilitate the separation and outflow of the solution from the ice (or ice + concentrated solution). Methods for separating and outflowing the solution from the ice (or ice + concentrated solution) include (but are not limited to) the following: natural outflow, extraction using a negative pressure device, and separation using physical centrifugation.

5. The freeze-concentration method according to claim 1, characterized in that: When heat is transferred to ice (or ice + concentrated solution) after a flow channel is set up, the heat transfer methods include (but are not limited to) the following: directly heating the ice (or ice + concentrated solution), the ice obtaining heat from the environment (e.g., the ice dissolving naturally), and setting a heat source at a specific location inside or outside the ice (or ice + concentrated solution) for heating.

6. In claim 5, the "specific location" of the heat source is a directional area, characterized in that: For example, when a dilute solution is frozen into ice (or ice + concentrated solution), the "specific orientation" is the area in the direction away from the "cooling surface" (hereinafter referred to as the orientation away from the "cooling surface") towards the ice (or ice + concentrated solution). This area can be inside or outside the ice, and can be in the orientation farthest from the "cooling surface" or in a relatively distant orientation.

7. The heat source positioned in a specific location according to claim 6, characterized in that: When setting up, the shape of the heat source includes (but is not limited to) the following: columnar (linear), plate (surface), point, spherical, etc.

8. The arrangement of the heat source according to claim 7, characterized in that: When a heat source is placed in a specific location, its orientation affects the freezing concentration and separation purification effects. For example, under normal circumstances, when the arrangement of columnar (linear) heat sources and plate (surface) heat sources is parallel to the "cooling surface" (referring to the cooling surface when freezing dilute solutions, the same below), and when the tangent of the spherical heat source is parallel to the "cooling surface", the effect of freeze concentration and separation purification will be improved.

9. The freeze-concentration method according to claim 1, characterized in that: It can be used for the freeze concentration and separation purification of heat-sensitive raw materials. For example, it can be used for the freeze concentration and separation purification of milk, wine, fruit juice, coffee, tea beverages, soy milk, chemical (raw) pharmaceutical solutions, and traditional Chinese medicine solutions.

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