Method and system for determining critical supersaturation degree of solution salt crystallization

Abstract

The invention is suitable for the technical field of solution salt crystallization dynamic process control, and provides a method and system for determining the critical supersaturation degree of solution salt crystallization, and the method comprises the following steps: determining the type and chemical formula of solution salt crystallization; determining crystal material parameters of the solution salt crystal according to the type and chemical formula of the solution salt crystal; determining the critical crystal nucleus size of the solution salt crystallization according to the crystal material parameters of the solution salt crystallization; and based on a preset critical supersaturation degree calculation model, determining the critical supersaturation degree of the solution salt crystallization according to the crystal material parameters and the critical crystal nucleus size of the solution salt crystallization. The method has the advantages of high calculation speed, high calculation efficiency, easy acquisition of calculation parameters and the like, overcomes the defect of difficult operation of a traditional test method, and provides theoretical technical support for development of a solution salt crystallization kinetic process control technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of solution salt crystallization kinetic process control, and in particular relates to a method and system for determining the critical supersaturation of solution salt crystallization. Background Art

[0002] The control technology for the kinetic process of salt solution crystallization is a key area of ​​expertise in chemical engineering, physical engineering, materials engineering, and other engineering fields. Supersaturation refers to the ratio of the solution concentration to the theoretical equilibrium concentration (i.e., solubility). A solution at this point is called a supersaturated solution. Supersaturation is the driving force behind salt crystallization. During the entire salt solution crystallization kinetic process, a supersaturated solution must first form. Then, when the supersaturation reaches a critical value (i.e., critical supersaturation), crystal nuclei are generated and further grow. Subsequently, the solution supersaturation decreases, and crystal growth stagnates and remains stable. The critical supersaturation of the crystalline substance directly influences the kinetics of crystal growth. Accurately calculating this critical supersaturation can avoid unnecessary time and technical complexity in subsequent crystallization operations. Because the nucleation process of salt crystals is extremely brief and difficult to observe and measure, the precise determination of the critical supersaturation of the crystalline substance in salt solutions is difficult.

[0003] At present, the numerical simulation technology of crystal growth has made some progress, but it can only provide a limited description of the crystal nucleation dynamics process at the nano-micro level, and it is difficult to accurately simulate and calculate the critical supersaturation of crystallized substances in salt solutions under complex macroscopic conditions.

[0004] For example, patent application number CN202310170535.2 discloses a molecular dynamics-based method for simulating the crystallization of inorganic salts, belonging to the field of micro- and nanoscale molecular simulation technology. Using Materials Studio software, molecular dynamics calculations are performed to simulate the crystallization process of inorganic salts under supercritical conditions, evaluating the effects of parameters such as temperature and pressure on the crystallization process, and providing a theoretical basis for further exploration of the crystallization process of inorganic salts. Patent application number CN202411015596.2 discloses a method for simulating the surface supersaturation of KDP crystals based on UDS, relating to the field of numerical simulation technology for crystal growth. The method includes: establishing a physical geometric model of the crystal growth tank, meshing the physical geometric model, and importing it into Fluent simulation software; establishing a mathematical model of the KDP crystal growth system, setting the computational domain and boundary conditions of the mathematical model, and calculating and solving the supersaturation distribution of the KDP crystal growth system. In general, numerical simulation methods still have shortcomings such as high computational complexity, high cost, and low universality, which limit their large-scale application. This limits the accurate calculation and evaluation of the critical supersaturation of crystallized substances in salt solutions. Therefore, in response to this situation, it is necessary to propose a method for calculating the critical supersaturation of solution salt crystallization to achieve the purpose of fast, convenient and accurate calculation. Summary of the Invention

[0005] The object of the present invention is to provide a method for determining the critical supersaturation of salt solution crystallization, aiming to solve the above technical problems.

[0006] The present invention is achieved by a method for determining the critical supersaturation of salt solution crystallization, comprising the following steps:

[0007] Determine the type and chemical formula of salt crystals from solution;

[0008] Determine the crystal material parameters of the solution salt crystal according to the type and chemical formula of the solution salt crystal;

[0009] Determine the critical crystal nucleus size of the solution salt crystallization according to the crystal material parameters of the solution salt crystallization;

[0010] Based on a preset critical supersaturation calculation model, the critical supersaturation of solution salt crystallization is determined according to the crystal material parameters and critical crystal nucleus size of the solution salt crystallization.

[0011] Furthermore, the crystal material parameters of the solution salt crystallization include crystal surface energy, unit cell size, molar volume, and crystallization temperature.

[0012] Furthermore, the step of determining the critical crystal nucleus size of the solution salt crystallization according to the crystal material parameters of the solution salt crystallization is specifically as follows:

[0013] According to the unit cell size of solution salt crystallization, the critical crystal nucleus size of solution salt crystallization is determined.

[0014] Furthermore, the critical crystal nucleus size of the solution salt crystallization is positively correlated with the unit cell size of the solution salt crystallization.

[0015] Furthermore, the calculation formula for the critical crystal nucleus size of the solution salt crystallization is:

[0016] ;

[0017] Where, is the critical nucleus size for solution salt crystallization; The minimum unit cell size for salt crystallization from solution.

[0018] Furthermore, the mathematical formula of the critical supersaturation calculation model is:

[0019] ;

[0020] Where S is the critical supersaturation of salt solution crystallization; V m is the molar volume of the salt crystallized from the solution; R is the molar gas constant; T is the crystallization temperature; The surface energy of the crystals of the solution salt; is the critical nucleus size for solution salt crystallization.

[0021] Another object of the present invention is to provide a system for determining the critical supersaturation of solution salt crystallization, which is used to implement the above-mentioned method for determining the critical supersaturation of solution salt crystallization, and comprises:

[0022] A salt crystal type determination module is used to determine the type and chemical formula of the salt crystals in the solution;

[0023] A crystal material parameter determination module is used to determine the crystal material parameters of the solution salt crystal according to the type and chemical molecular formula of the solution salt crystal;

[0024] A critical crystal nucleus size determination module is used to determine the critical crystal nucleus size of the solution salt crystallization according to the crystal material parameters of the solution salt crystallization;

[0025] The critical supersaturation determination module is used to determine the critical supersaturation of solution salt crystallization based on a preset critical supersaturation calculation model and according to the crystal material parameters and critical crystal nucleus size of the solution salt crystallization.

[0026] The present invention provides a method for determining the critical supersaturation of solution salt crystallization, which has the advantages of fast calculation speed, high calculation efficiency and easy acquisition of calculation parameters. It makes up for the shortcomings of traditional testing methods that are difficult to operate, and provides theoretical and technical support for the development of solution salt crystallization kinetic process control technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic flow chart of a method for determining the critical supersaturation of salt solution crystallization provided in an embodiment of the present invention.

[0028] Figure 2 A schematic diagram of a system for determining the critical supersaturation of salt solution crystallization provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] The embodiment of the present invention is based on the Gibbs-Curie-Wulff surface energy balance theory and proposes a solid-liquid yielding equation (SLY formula) for calculating the critical supersaturation of solution salt crystallization. Based on the SLY formula, the critical supersaturation of solution salt crystallization is quickly and accurately calculated using basic physical property parameters of crystals. Specifically, Figure 1 As shown, in one embodiment of the present invention, a method for determining the critical supersaturation of salt crystallization in a solution is provided, comprising the following steps:

[0031] S100, determining the type and chemical formula of the salt crystals in the solution;

[0032] S200, determining the crystal material parameters of the solution salt crystal according to the type and chemical formula of the solution salt crystal;

[0033] S300, determining a critical crystal nucleus size for solution salt crystallization according to crystal material parameters of the solution salt crystallization;

[0034] S400 , based on a preset critical supersaturation calculation model, determining the critical supersaturation of the solution salt crystallization according to the crystal material parameters and critical crystal nucleus size of the solution salt crystallization.

[0035] As a preferred embodiment of the present invention, in step S100, since the specific chemical formula of the salt crystal determines its crystal material parameters, the crystal material parameters of the solution salt crystal can be selected and determined by determining the type of salt crystal in the solution and its corresponding specific chemical formula; for example, if the type of salt crystal in the solution is sodium chloride crystal, its crystal material parameters can be determined by the chemical formula of the sodium chloride crystal NaCl. In practical applications, the crystal material parameters of the solution salt crystal can be selected from crystal surface energy, unit cell size, molar volume, crystallization temperature, etc. The crystal surface energy of sodium chloride crystal is 0.087 J / m 2, the molar volume is 24.7×10 -6 m 3 / mol, and the minimum unit cell size is 5.64×10 -10 m, and the crystallization temperature was set to 293.15 K.

[0036] As a preferred embodiment of the present invention, the step of determining the critical nucleus size of the solution salt crystallization according to the crystal material parameters of the solution salt crystallization, i.e., step S300, is specifically as follows:

[0037] According to the unit cell size of solution salt crystallization, the critical crystal nucleus size of solution salt crystallization is determined.

[0038] In practical applications, the critical nucleus size of solution salt crystallization is positively correlated with the unit cell size of solution salt crystallization.

[0039] Specifically, the critical crystal nucleus size of the solution salt crystallization is twice the minimum unit cell size; the calculation formula for the critical crystal nucleus size of the solution salt crystallization is:

[0040] ;

[0041] Where, is the critical nucleus size for solution salt crystallization (usually in m); It is the minimum unit cell size of solution salt crystallization (usually in m).

[0042] As a preferred embodiment of the present invention, a critical supersaturation calculation model can be constructed based on the Gibbs-Curie-Wulff surface energy balance theory; the mathematical formula of the critical supersaturation calculation model (SLY formula) is:

[0043] ;

[0044] Where S is the critical supersaturation of salt solution crystallization (dimensionless); V m is the molar volume of the salt crystals from the solution (usually in m 3 ); R is the molar gas constant, which is 8.314 J / (mol·K); T is the crystallization temperature (usually in K); is the surface energy of the crystal of the solution salt (usually in J / m 2 ); It is the critical nucleus size for solution salt crystallization (usually in m).

[0045] The critical supersaturation of sodium chloride crystals in the sodium chloride solution was calculated according to the method provided in the above embodiment and compared with the experimental measurement results disclosed in the existing literature (Gregson FKA, Robinson JF, Miles REH, et al. Drying kinetics of salt solution droplets: Water evaporation rates and crystallization[J]. The Journal of Physical Chemistry B, 2018, 123(1): 266-276.). The comparison results are shown in Table 1.

[0046] Table 1

[0047]

[0048] As can be seen from Table 1, the method for determining the critical supersaturation of salt solution crystallization provided by the present invention can accurately calculate the critical supersaturation of salt solution crystallization, with a deviation of less than 7% compared with existing experimental results. This method has the advantages of fast calculation speed, high computational efficiency, and easy parameter acquisition, which overcomes the operational difficulty of traditional testing methods.

[0049] like Figure 2 As shown, another object of the present invention is to provide a system for determining the critical supersaturation of solution salt crystallization, which is used to implement the above-mentioned method for determining the critical supersaturation of solution salt crystallization, and comprises:

[0050] The salt crystal type determination module 10 is used to determine the type and chemical formula of the salt crystals in the solution;

[0051] The crystal material parameter determination module 20 is used to determine the crystal material parameters of the solution salt crystal according to the type and chemical formula of the solution salt crystal;

[0052] A critical crystal nucleus size determination module 30 is used to determine the critical crystal nucleus size of the solution salt crystal according to the crystal material parameters of the solution salt crystal;

[0053] The critical supersaturation determination module 40 is used to determine the critical supersaturation of the solution salt crystallization based on a preset critical supersaturation calculation model and according to the crystal material parameters and critical crystal nucleus size of the solution salt crystallization.

[0054] As a preferred embodiment of the present invention, since the specific chemical molecular formula of the salt crystal determines its crystal material parameters, the salt crystal type determination module 10 determines the salt crystal type in the solution and its corresponding specific chemical molecular formula, and thus the crystal material parameters of the solution salt crystal can be selected and determined. In actual applications, the crystal material parameters of the solution salt crystal can be selected from crystal surface energy, unit cell size, molar volume, crystallization temperature, etc.

[0055] As a preferred embodiment of the present invention, the critical crystal nucleus size determining module 30 specifically determines the critical crystal nucleus size of the solution salt crystallization according to the unit cell size of the solution salt crystallization.

[0056] In practical applications, the critical nucleus size of solution salt crystallization is positively correlated with the unit cell size of solution salt crystallization.

[0057] Specifically, the critical crystal nucleus size of the solution salt crystallization is twice the minimum unit cell size; the calculation formula of the critical crystal nucleus size of the solution salt crystallization is the same as the above embodiment.

[0058] As a preferred embodiment of the present invention, a critical supersaturation calculation model can be constructed based on the Gibbs-Curie-Wulff surface energy balance theory; the mathematical formula of the critical supersaturation calculation model is the same as that of the above embodiment.

[0059] It should be noted that the above-mentioned modules can be implemented in the form of a computer program, which can be run on a computer device. The memory of the computer device can store the computer program constituting each module so that the processor executes each step of the above-mentioned method for determining the critical supersaturation of salt crystallization in a solution.

[0060] It should be understood that, although the various steps in the flow chart of each embodiment of the present invention are shown in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence according to the order indicated by the arrows. Unless otherwise specified herein, the execution of these steps is not strictly limited in order, and these steps can be performed in other orders. Moreover, at least a portion of the steps in each embodiment may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0061] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory.

[0062] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for determining the critical supersaturation of salt solution crystallization, characterized in that: The following steps are involved: Determine the type and chemical formula of salt crystals from solution; Determine the crystal material parameters of the solution salt crystal according to the type and chemical formula of the solution salt crystal; Determine the critical crystal nucleus size of the solution salt crystallization according to the crystal material parameters of the solution salt crystallization; Based on a preset critical supersaturation calculation model, the critical supersaturation of solution salt crystallization is determined according to the crystal material parameters and critical crystal nucleus size of the solution salt crystallization.

2. The method for determining the critical supersaturation of solution salt crystallization according to claim 1, wherein: The crystal material parameters of the solution salt crystallization include crystal surface energy, unit cell size, molar volume, and crystallization temperature.

3. The method for determining the critical supersaturation of solution salt crystallization according to claim 2, wherein: The steps for determining the critical crystal nucleus size of the solution salt crystallization according to the crystal material parameters of the solution salt crystallization are specifically as follows: According to the unit cell size of solution salt crystallization, the critical crystal nucleus size of solution salt crystallization is determined.

4. The method for determining the critical supersaturation of solution salt crystallization according to claim 3, wherein: The critical crystal nucleus size of the solution salt crystallization is positively correlated with the unit cell size of the solution salt crystallization.

5. The method for determining the critical supersaturation of solution salt crystallization according to claim 4, wherein: The calculation formula for the critical crystal nucleus size of the solution salt crystallization is: ； Where, is the critical nucleus size for solution salt crystallization; The minimum unit cell size for salt crystallization from solution.

6. The method for determining the critical supersaturation of solution salt crystallization according to claim 2 or 5, characterized in that: The mathematical formula of the critical supersaturation calculation model is: ； Where S is the critical supersaturation of salt solution crystallization; V m is the molar volume of the salt crystallized from the solution; R is the molar gas constant; T is the crystallization temperature; The surface energy of the crystals of the solution salt; is the critical nucleus size for solution salt crystallization.

7. A system for determining the critical supersaturation of a solution salt crystallization, for implementing the method for determining the critical supersaturation of a solution salt crystallization according to any one of claims 1 to 6, characterized in that: include: A salt crystal type determination module is used to determine the type and chemical formula of the salt crystals in the solution; A crystal material parameter determination module is used to determine the crystal material parameters of the solution salt crystal according to the type and chemical molecular formula of the solution salt crystal; A critical crystal nucleus size determination module is used to determine the critical crystal nucleus size of the solution salt crystallization according to the crystal material parameters of the solution salt crystallization; The critical supersaturation determination module is used to determine the critical supersaturation of solution salt crystallization based on a preset critical supersaturation calculation model and according to the crystal material parameters and critical crystal nucleus size of the solution salt crystallization.

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