A method for freeze concentration

Abstract

This invention belongs to the field of cryogenic concentration technology, specifically relating to a cryogenic concentration method. It involves freezing a dilute solution into a solid or solid-liquid mixture, using gas as an energy medium, and leveraging the solid structure of the frozen material's surface and interior. Heat is transferred to the frozen material by applying negative or positive pressure. Through dissolution and separation, solutions are collected in stages to obtain solutions of different concentrations. Solutions meeting the target concentration are transferred to the next stage; solutions not meeting the target concentration are reused to further increase the concentration. This method improves the efficiency of cryogenic concentration and separation purification, is simple to operate, and is suitable for applications in food, cosmetics, biopharmaceuticals, petrochemicals, metal processing, and environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of freeze concentration technology, specifically a freeze concentration method. Background Technology

[0002] Existing freeze concentration techniques utilize the solid-liquid phase relationship between dilute solutions and ice below its freezing point, achieving concentration through solid-liquid separation. This method primarily employs two approaches: suspension crystallization freeze concentration and (interfacial) progressive freeze concentration. Additionally, there are freeze concentration methods that utilize the natural melting of ice or the heating and melting of ice (belonging to the traditional conventional heating-dissolution freeze concentration method). However, all three existing freeze concentration methods suffer from low concentration efficiency.

[0003] Suspension crystallization freeze-concentration and progressive freeze-concentration methods achieve concentration through solid-liquid (ice crystals and liquid) separation. Both suffer from problems such as solute entrainment by ice crystals and low concentration efficiency. While conventional heating-dissolving (including natural dissolution) methods for frozen materials do not have the efficiency problem caused by solute entrainment, they face a long-standing and severely inefficient issue: heating frozen materials too quickly degrades concentration, while low-temperature heating (such as at refrigeration temperatures) yields better results (relative to higher temperatures), but is extremely time-consuming. Therefore, when using conventional heating-dissolving freeze-concentration methods, technicians generally prefer natural dissolution at room temperature (using ambient energy) or heating at refrigeration temperatures. Conventional heating-dissolving freeze-concentration (including natural dissolution at room temperature) is not only time-consuming but also less efficient than the previous two methods (those that achieve concentration through solid-liquid separation). Therefore, most of the current mainstream freezing concentration technologies use the first two methods (concentration through solid-liquid separation).

[0004] Existing cryogenic concentration methods involve freezing a dilute solution to obtain a solid or solid-liquid mixture, then crushing the solid or mixture, or separating the solid-liquid mixture before crushing the solid. A dry gas is used as the energy medium to penetrate the crushed solid and transfer heat, allowing the solution to be collected in stages for cryogenic concentration. This method improves the dissolution and separation efficiency by crushing the frozen material (solid or solid-liquid mixture) and allowing the gas, acting as the energy medium, to penetrate the crushed material, thus improving the cryogenic concentration effect and efficiency. However, this method requires a dedicated crushing device to structurally crush the frozen material before dissolution and separation during the cryogenic concentration process, increasing the operational difficulty. For example, frozen material at low temperatures (even deep cryogenic temperatures at high concentrations) acts as a condenser for the air, rapidly absorbing water vapor. Furthermore, the increased contact area between the crushed frozen material and the air, coupled with the interference from the air's heat, necessitates strict control of the environment during the crushing and dissolution stages to avoid impacting the cryogenic concentration efficiency. At low temperatures (especially at deep cryogenic temperatures), each additional step increases the complexity of the operation, and the increased number of steps also leads to greater complexity when performing multi-stage freeze-concentration combinations. Summary of the Invention

[0005] To address the problems existing in the prior art, the main objective of this invention is to propose a cryogenic concentration method that uses gas as an energy medium and leverages the solid structure characteristics of the surface and interior of the cryogenic material. By using negative or positive pressure to force the gas through the cryogenic material to transfer heat, this method reduces the complexity and difficulty of existing cryogenic concentration techniques, improves the efficiency of cryogenic concentration, and simplifies the operation.

[0006] According to one aspect of the present invention, the present invention provides the following technical solution:

[0007] A cryogenic concentration method involves freezing a dilute solution into a solid or solid-liquid mixture, using gas as an energy medium. Leveraging the solid structure of the frozen material's surface and interior, heat is transferred through the gas via negative or positive pressure. The solution is then separated and collected in stages to obtain solutions of different concentrations. Solutions meeting the target concentration are transferred to the next stage; solutions not meeting the target concentration are reused to further increase the concentration.

[0008] In a preferred embodiment of the cryogenic concentration method described in this invention, during the freezing of the dilute solution, a dense solid layer is prevented from forming on the surface of the freezing material in the gas inflow / outflow direction, or the density of the solid layer on the surface of the freezing material in the gas inflow / outflow direction is less than that of the surface solid layer in other directions, or the dense solid layer formed on the surface of the freezing material in the gas inflow / outflow direction is thinner than that formed on the surface in other directions. The internal structural characteristics of the freezing material allow gas to pass through it. For example, during freezing, the direction of heat transfer can be controlled to be perpendicular to the gas inflow / outflow direction, thus preventing the formation of a dense solid layer on the surface of the freezing material in the gas inflow / outflow direction. Methods for controlling the direction of heat transfer include, but are not limited to, selecting an appropriate cold source location and designing the combination of the freezing apparatus. Alternatively, selecting a material with low thermal conductivity in the gas inflow / outflow direction of the freezing apparatus can limit heat transfer in that direction, resulting in a thinner and less dense solid layer formed on the surface of the freezing material in that direction.

[0009] In a preferred embodiment of the cryogenic concentration method described in this invention, the surface solid layer of the cryogenic material in the gas inlet and outlet directions is fractured by the gas pressure difference, and the solution is extracted by negative or positive pressure after adjusting the gas pressure. During the extraction process, the energy medium gas passes through the cryogenic material to transfer heat to it.

[0010] As a preferred embodiment of the cryogenic concentration method of the present invention, the surface solid layer of the cryogenic material in the gas inlet and outlet direction is fractured by the gas pressure difference specifically by: forming a pressure difference by introducing high-pressure gas to fracture the surface solid layer of the cryogenic material in the gas inlet and outlet direction, or forming a pressure difference by negative pressure extraction to fracture the surface solid layer of the cryogenic material in the gas inlet and outlet direction.

[0011] In a preferred embodiment of the cryogenic concentration method described in this invention, the dense solid layer on the surface of the cryogenic material in the gas inlet and outlet directions is broken by mechanical means, and the gas is allowed to pass through the cryogenic material and transfer heat to it by utilizing the internal structural characteristics of the cryogenic material.

[0012] In a preferred embodiment of the cryogenic concentration method described in this invention, a channel is provided in the cryogenic material to allow gas to pass through the cryogenic material and transfer heat to it.

[0013] In a preferred embodiment of the freeze-concentration method of the present invention, a gas channel and a solution channel are pre-set during freezing; or a gas channel and a solution channel are provided on the frozen material after freezing is completed.

[0014] In a preferred embodiment of the freeze-concentration method described in this invention, the gas channel and the solution channel are set as the same channel, or different gas channels and solution channels are set independently.

[0015] In a preferred embodiment of the cryogenic concentration method described in this invention, the gas used as the energy medium is a gas that does not interfere with the dissolution and separation of the cryogenic material, such as air, inert gas, carbon dioxide gas, nitrogen gas, etc.

[0016] In a preferred embodiment of the freeze-concentration method described in this invention, heat is transferred to the freezing material using the energy carried by the energy medium gas, and the energy medium gas is replenished and recycled; or the air energy carried by the air itself is used to transfer heat to the freezing material; the energy medium gas may be dried as needed before transferring heat to the freezing material.

[0017] According to another aspect of the present invention, the present invention provides the following technical solution:

[0018] The above-mentioned freeze concentration method has applications in the fields of food, cosmetics, biomedicine, petrochemicals, metal processing, and environmental protection.

[0019] The above-mentioned freeze concentration method has applications in the fields of milk, vinegar (including vinegar-containing foods, vinegar beverages, condiments, etc.), alcoholic beverages, beverages (such as fruit juice, coffee, tea, soy milk, soy milk, etc.), chemical liquids, traditional Chinese medicine liquids, plant extracts, petroleum refining, chemical refining, metal separation and refining, seawater refining, and wastewater treatment.

[0020] An application of the above-mentioned freeze concentration method in the field of freeze concentration and separation purification of heat-sensitive raw materials.

[0021] The above-mentioned freeze concentration method is applied in the fields of freeze concentration and separation purification of milk, vinegar (including vinegar-containing foods, vinegar beverages, condiments, etc.), alcoholic beverages, beverages (such as fruit juice, coffee, tea, soy milk, soy milk, etc.), chemical liquids, traditional Chinese medicine liquids, plant extracts, petroleum purification, chemical purification, metal separation and purification, seawater purification, wastewater treatment, etc.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention proposes a freeze-concentration method that freezes a dilute solution into a solid or solid-liquid mixture. Using gas as the energy medium, and leveraging the solid structure of the frozen material's surface and interior, heat is transferred through the gas via negative or positive pressure. Through dissolution and separation, solutions of different concentrations are obtained. Solutions meeting the target concentration are transferred to the next stage; solutions not meeting the target concentration are reused to further increase the concentration. This method eliminates the need for a dedicated crushing device to structurally break up the frozen material before dissolution and separation, simplifying the freeze-concentration process and improving its effectiveness and efficiency. This method is suitable for applications in food, cosmetics, biopharmaceuticals, petrochemicals, metal processing, and environmental protection. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some preferred embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0025] Figure 1 This is a process flow diagram of the freeze concentration method of the present invention.

[0026] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0027] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] like Figure 1 As shown, this invention provides a method for cryogenic concentration, which freezes a dilute solution into a solid or solid-liquid mixture. Using gas as an energy medium, and taking advantage of the solid structure characteristics of the surface and interior of the cryogenic material, the gas is forced through the cryogenic material by negative or positive pressure to achieve heat transfer. Through dissolution and separation, solutions are collected in segments to obtain solutions of different concentrations. Solutions meeting the target concentration are transferred to the next stage; solutions not meeting the target concentration are reused to further increase the solution concentration.

[0029] In one embodiment of the present invention, during the freezing of a dilute solution, a dense solid layer is not formed on the surface of the freezing material in the direction of gas entry and exit, or the density of the solid layer on the surface of the freezing material in the direction of gas entry and exit is less than that of the solid layer on the surface in other directions, or the dense solid layer formed on the surface of the freezing material in the direction of gas entry and exit is thinner than the dense solid layer formed on the surface in other directions, thereby utilizing the internal structural characteristics of the freezing material to allow gas to pass through the freezing material.

[0030] In specific implementations of this invention, several preferred methods can be selected to allow gas to pass through the freezing material:

[0031] (1) The surface solid layer of the freezing material in the direction of gas inlet and outlet is fractured by the gas pressure difference. After adjusting the gas pressure, the solution is extracted by negative or positive pressure. During the extraction process, the energy medium gas passes through the freezing material to transfer heat to it. The surface solid layer of the freezing material in the direction of gas inlet and outlet is fractured by the gas pressure difference. Specifically, the surface solid layer of the freezing material in the direction of gas inlet and outlet is fractured by introducing high-pressure gas to form a pressure difference, or by forming a pressure difference by negative pressure extraction.

[0032] (2) The dense solid layer on the surface of the freezing material in the direction of gas entry and exit is destroyed by mechanical means, and the gas is allowed to pass through the freezing material by utilizing the internal structural characteristics of the freezing material, or a channel is set in the freezing material to allow the gas to pass through the freezing material and transfer heat to it.

[0033] (3) A channel is provided in the freezing material to allow gas to pass through the freezing material and transfer heat to it; preferably, a gas channel and a solution channel are preset during freezing; or a gas channel and a solution channel are provided on the freezing material after freezing is completed. More preferably, the gas channel and the solution channel are set as the same channel, or different gas channels and solution channels are set independently.

[0034] In one embodiment of the present invention, the gas used as the energy medium is a gas that does not interfere with the dissolution and separation of the cryogenic material, such as air, inert gas, carbon dioxide gas, nitrogen gas, etc.

[0035] In one embodiment of the present invention, the energy carried by the energy medium gas is used to transfer heat to the freezing material, and the energy medium gas is replenished and recycled; or the air energy carried by the air itself is used to transfer heat to the freezing material; the energy medium gas can be dried as needed before transferring heat to the freezing material.

[0036] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A freeze concentration method characterized by, The dilute solution is frozen into solid or solid-liquid mixed state frozen material, gas is used as energy medium, the gas is made to pass through the frozen material by negative pressure or positive pressure according to the solid structure characteristics of the frozen material surface and interior, and heat transfer is realized; the solution is obtained by dissolving and separating.

2. The freeze concentration method according to claim 1, characterized by, When the dilute solution is frozen, the surface of the frozen material in the gas inlet and outlet direction is not formed into dense solid layer, or the dense degree of the solid layer of the surface in the gas inlet and outlet direction is smaller than that of the surface in other directions, or the dense solid layer of the surface in the gas inlet and outlet direction is thinner than that of the surface in other directions, and the gas is made to pass through the frozen material according to the internal structure characteristics of the frozen material.

3. The freeze concentration method according to claim 1, characterized by, The solid layer of the surface of the frozen material in the gas inlet and outlet direction is cracked by the pressure difference of the gas, and then the solution is extracted by negative pressure or positive pressure after adjusting the gas pressure, and the energy medium gas is made to pass through the frozen material to transfer heat.

4. The freeze concentration method according to claim 1, characterized by, The dense solid layer of the surface of the frozen material in the gas inlet and outlet direction is destroyed by mechanical method, and the gas is made to pass through the frozen material according to the internal structure characteristics of the frozen material to transfer heat.

5. The freeze concentration method according to claim 1, characterized by, The channel is set in the frozen material to make the gas pass through the frozen material to transfer heat.

6. The freeze concentration method according to claim 5, characterized in that, The gas channel and the solution channel are set as the same channel, or the different gas channel and the solution channel are set independently.

7. The freeze concentration method according to claim 6, characterized in that, The gas as energy medium is the gas which does not interfere with the dissolution and separation of the frozen material.

8. The freeze concentration method of claim 1, wherein, The energy medium gas is used to transfer heat to the frozen material, and the energy medium gas is recycled by supplementing energy; or the air itself is used to transfer heat to the frozen material.

9. The freeze concentration method of claim 1, wherein, 10. The application of the frozen concentration method in the fields of food, cosmetics, biological medicine, petroleum chemical industry, metal processing, environmental protection treatment. ​

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