A simulation system of a mixing and clarifying tank and a calculation method thereof

Abstract

The application relates to a simulation system of a mixing and clarifying tank and a calculation method thereof, which comprises an initial external variable input module, an intermediate process external variable input module, a mixing chamber simulation calculation module, a clarifying chamber simulation calculation module and an iterative control module. By setting initial flow parameter and mixing and clarifying tank equipment parameter, the change of external flow parameter in the simulation simulation process is set, the running state of the mixing chamber is simulated and calculated according to the set initial flow parameter and the related data of the intermediate process external variable, and the running state of the clarifying chamber is simulated and calculated, and the minimum time unit and the iteration number of the iterative calculation process are controlled to perform iterative operation. By adopting the method disclosed in the application, various theoretical models such as pressure balance, weir flow model, extraction balance and heterogeneous mixing process are comprehensively applied, a simulation system of liquid volume and flow of the mixing and clarifying tank is constructed through a numerical simulation method, and reliable data support is provided for the establishment of an intelligent control system for rare earth extraction and separation.

Description

Technical Field

[0001] This invention belongs to the field of solvent extraction and separation technology, specifically relating to a simulation system and calculation method for a mixing clarification tank. Background Technology

[0002] As an important strategic resource, rare earth elements are key raw materials for many high-tech industrial sectors. Currently discovered rare earth minerals (such as bastnaesite, monazite, and ion-adsorption type rare earth minerals) are all associated minerals of several to more than a dozen rare earth elements. The high-purity, high-quality, and low-cost separation of mixed rare earth elements is crucial for the comprehensive and efficient utilization of rare earth resources.

[0003] Since the 1970s, the cascade extraction theory established by Academician Xu Guangxian and others has made China's rare earth separation theory and technology world-leading. Under the guidance of this theory, computer simulation technology and linked extraction separation technology have been further developed, continuously leading the innovation of my country's rare earth separation technology and industry. Currently, solvent extraction separation methods based on hydrometallurgical equipment such as mixing clarification tanks have become the mainstream technology in the field of rare earth separation.

[0004] Entering the 21st century, against the backdrop of the comprehensive transformation and upgrading of my country's industrial manufacturing industry and the deep integration of computer technology with traditional manufacturing, higher development requirements have been put forward for rare earth extraction and separation technology. The full automation and intelligentization of the extraction and separation process has become an increasingly urgent practical need.

[0005] In the research of intelligent control systems, most patents and articles focus on the theoretical study of extraction equilibrium problems, paying less attention to the constantly changing volume and flow balance problems that exist in the actual operation of mixing and clarification tanks. However, a large amount of practical experience in rare earth extraction and separation shows that the volume and flow balance problems of mixing and clarification tanks are crucial to the control of extraction and separation production lines.

[0006] As the operating status of the production line changes, the volume of the two-phase tank and the flow rates entering and exiting the mixing and clarification tank also constantly change, exhibiting significant nonlinearity and hysteresis characteristics. The volume and flow balance control of the tank directly affects the quality of the rare earth products output from the extraction and separation production line. Constructing a simulation system for the mixing and clarification tank in the rare earth extraction and separation process is a crucial step in building an intelligent control system for rare earth extraction and separation. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a simulation system and calculation method for a mixing clarification tank, which is applied to the rare earth extraction and separation process. Addressing the volume balance and flow balance issues in the rare earth extraction and separation process, the invention comprehensively applies multiple theoretical models, including pressure balance, weir flow model, extraction balance, and heterogeneous mixing process, and uses numerical calculation methods to simulate the actual operation of the mixing clarification tank, providing reliable data support for the construction of an intelligent control system for rare earth extraction and separation.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] In a first aspect, a simulation system for a mixing and clarification tank is provided. The system includes an initial external variable input module for setting initial flow parameters and mixing and clarification tank equipment parameters. The single-stage tank of the mixing and clarification tank includes a mixing chamber and a clarification chamber. The aqueous phase and organic phase of the single-stage tank flow countercurrently between the stages of the tank.

[0010] The intermediate process external variable input module is used to set the changes in external flow parameters during the simulation process;

[0011] The mixing chamber simulation calculation module is used to simulate and calculate the operating status of the mixing chamber based on the relevant data in the initial external variable input module and the intermediate process external variable input module.

[0012] The clarification chamber simulation calculation module is used to simulate and calculate the operating status of the clarification chamber based on the relevant data in the initial external variable input module and the intermediate process external variable input module.

[0013] And an iteration control module, used to control the minimum time unit and number of iterations in the iterative calculation process for iterative computation.

[0014] Furthermore, the initial flow parameters include the initial flow rate of the organic phase and the initial flow rate of the aqueous phase entering the mixing and clarification tank from the outside.

[0015] Furthermore, the parameters of the mixing and clarification tank equipment include the total number of tank stages, mixing chamber volume, initial mixing chamber ratio, clarification chamber volume, organic phase overflow weir height in the clarification chamber, aqueous phase overflow weir height in the clarification chamber, equivalent organic phase overflow weir width in the clarification chamber, and equivalent aqueous phase overflow weir width in the clarification chamber.

[0016] Furthermore, the external flow parameters include the flow rates of the organic phase and the aqueous phase entering the mixing and clarification tank from the outside during the simulation process.

[0017] Furthermore, the basic formulas used by the mixing chamber simulation calculation module for simulation calculations include the heterogeneous mixing process formula and the extraction equilibrium formula.

[0018] Furthermore, the formula for the heterogeneous mixing process is described as follows:

[0019]

[0020] Where: γ(t) is the ratio at time t (organic phase volume / aqueous phase volume);

[0021] γ(t+1 is the ratio at time t+1 (organic phase volume / aqueous phase volume);

[0022] γ F The ratio of the feed liquid to the organic phase flow rate (aqueous phase flow rate);

[0023] F represents the total feed flow rate;

[0024] V represents the total volume of the storage tank.

[0025] Furthermore, in the mixing and clarification tank containing components A and B, the extraction equilibrium formula is described as follows:

[0026]

[0027] in: This represents the molar concentration of component A in the organic phase.

[0028] A represents the molar concentration of component A in the aqueous phase;

[0029] This represents the molar concentration of component B in the organic phase.

[0030] B represents the molar concentration of component B in the aqueous phase.

[0031] β A / B The extraction separation coefficient is denoted as .

[0032] Furthermore, the basic formulas used in the clarification chamber simulation calculation module include the two-phase pressure balance formula and the weir flow formula. The two-phase pressure balance formula is described as follows:

[0033]

[0034] Where: ρ o The density of the organic phase in the clarifier;

[0035] h o The height of the organic phase in the clarifier;

[0036] ρ a The density of the aqueous phase in the clarification chamber;

[0037] h a The water phase height in the clarifier;

[0038] H is the height of the water phase overflow weir;

[0039] H0 is the water head height above the water phase weir.

[0040] Furthermore, the weir flow type is a thin-walled weir, and the weir flow formula is described as follows:

[0041]

[0042] in:

[0043] Q represents the weir flow rate of the aqueous or organic phase per unit time;

[0044] m is the weir flow coefficient, which ranges from 0 to 10 depending on the structure of the overflow weir.

[0045] B is the equivalent weir width;

[0046] g is the gravitational acceleration constant;

[0047] H0 is the water head height above the weir.

[0048] Secondly, a simulation calculation method for a mixing clarifier tank is provided, the method being based on a simulation system for a mixing clarifier tank as described in the first aspect of the present invention and any optional embodiment thereof, the method comprising the following steps:

[0049] S1. Set the initial flow parameters and mixing and clarification tank equipment parameters. The single-stage tank of the mixing and clarification tank includes a mixing chamber and a clarification chamber. The aqueous phase and organic phase of the single-stage tank flow countercurrently between the stages of the tank.

[0050] S2. Set the changes in external flow parameters during the simulation process;

[0051] S3. Simulate and calculate the operating status of the mixing chamber based on the relevant data set in steps S1 and S2;

[0052] S4. Simulate and calculate the operating status of the clarification chamber based on the relevant data set in steps S1 and S2.

[0053] S5. Control the minimum time unit and number of iterations in the iterative calculation process to perform iterative calculations.

[0054] The beneficial technical effects of this invention are as follows: by using the simulation calculation method of the mixing clarification tank disclosed in this invention, the volume balance and flow balance process during the operation of the extraction and separation production line can be simulated by theoretical calculation; based on the simulation results, the operating status of the extraction and separation production line can be analyzed and predicted, providing theoretical basis and data support for the control of the production line; the volume and flow balance simulation system is a key link in the construction of an intelligent control system for rare earth extraction and separation, and is one of the important foundations for realizing the intelligentization of rare earth separation production. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the structure of a simulation system for a mixing and clarification tank as shown in Embodiment 1 of the present invention;

[0056] Figure 2 This is a schematic diagram of a 50-stage series tank with countercurrent flow of organic and aqueous phases, as shown in Embodiment 1 of the present invention.

[0057] Figure 3 This is a schematic diagram of a typical single-stage mixing and clarification tank shown in Embodiment 1 of the present invention;

[0058] Figure 4 This is a schematic diagram of the organic phase overflow weir in a typical mixing and clarification tank as shown in Embodiment 1 of the present invention;

[0059] Figure 5 This is a schematic diagram of the water phase overflow weir in a typical mixing and clarification tank as shown in Embodiment 1 of the present invention;

[0060] Figure 6 This is a schematic diagram of the heterogeneous mixing process in the mixing chamber shown in Embodiment 1 of the present invention;

[0061] Figure 7 This is a schematic diagram of the two-phase pressure balance in the clarification chamber shown in Embodiment 1 of the present invention;

[0062] Figure 8 This is a schematic diagram of a typical thin-walled weir flow shown in Embodiment 1 of the present invention;

[0063] Figure 9 This is a graph showing the trend of organic phase flow rate over time in stages 5, 25, and 45 of the extraction and separation tank in Embodiment 1 of the present invention.

[0064] Figure 10 This is a graph showing the trend of changes over time between the 5th, 25th, and 45th mixing chambers of the extraction and separation tank in Embodiment 1 of the present invention.

[0065] Figure 11 This is a graph showing the trend of the flow rate of the aqueous phase in the extraction and separation tank at stages 5, 25, and 45 over time in Embodiment 1 of the present invention. Detailed Implementation

[0066] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0067] Example 1

[0068] like Figure 1 As shown, this embodiment of the invention provides a simulation system for a mixing and clarification tank, including an initial external variable input module, an intermediate process external variable input module, a mixing chamber simulation calculation module, a clarification chamber simulation calculation module, and an iterative control module.

[0069] The mixing and clarification tank used in rare earth extraction and separation processes consists of multiple tanks connected in series, such as... Figure 2 As shown in the illustration, this embodiment uses a rare earth extraction and separation production line comprising a 50-stage series tank as an example. At t=0, this tank is in a state of volume and flow equilibrium, and the key parameters within the tank are basically stable. In this series tank, the organic phase and the aqueous phase flow counter-currently. The organic phase enters from stage 1 and exits from stage 50; the aqueous phase enters from stage 50 and exits from stage 1. Figure 3 As shown, the single-stage tank consists of a mixing chamber and a clarification chamber, and the aqueous phase and organic phase in the single-stage tank flow countercurrently between the tanks of each stage.

[0070] The initial external variable input module is used to set the initial flow parameters and the parameters of the mixing and clarification tank equipment. The initial flow parameters include, but are not limited to, the initial flow rate of the organic phase and the initial flow rate of the aqueous phase entering the mixing and clarification tank from the outside.

[0071] The parameters of the mixing and clarification tank equipment include, but are not limited to, the total number of tank stages, mixing chamber volume, initial mixing chamber ratio, clarification chamber volume, organic phase overflow weir height, aqueous phase overflow weir height, equivalent organic phase overflow weir width, and equivalent aqueous phase overflow weir width. The schematic diagrams of the organic phase overflow weir and the aqueous phase overflow weir are shown below. Figure 4 and Figure 5 As shown in Table 1, the relevant parameters of the initial external variable input module are as follows.

[0072] Table 1 Initial flow rate parameters and equipment parameters of the mixing and clarification tank

[0073]

[0074] The intermediate process external variable input module is used to set the changes in external flow parameters during the simulation. External flow parameters include, but are not limited to, the flow rates of the organic phase and the aqueous phase entering the mixing and clarification tank from the outside during the simulation.

[0075] The relevant parameters of the intermediate process external variable input module are shown in Table 2.

[0076] Table 2 External flow parameters in the intermediate process external variable input module

[0077]

[0078] The mixing chamber simulation calculation module is used to simulate and calculate the operating status of the mixing chamber based on relevant data from the initial external variable input module and the intermediate process external variable input module.

[0079] The basic formulas used in the mixing chamber simulation calculation module include, but are not limited to, formulas for heterogeneous mixing processes and extraction equilibrium formulas.

[0080] The formula for a heterogeneous mixing process is described as follows:

[0081]

[0082] like Figure 6 As shown, where:

[0083] γ(t) represents the ratio (organic phase volume / aqueous phase volume) at time t;

[0084] γ(t+1) represents the ratio (organic phase volume / aqueous phase volume) at time t+1;

[0085] γ F The ratio of the feed liquid to the organic phase flow rate (aqueous phase flow rate);

[0086] F represents the total feed flow rate;

[0087] V represents the total volume of the storage tank.

[0088] Taking an extraction and separation system containing two components, A and B, as an example, the extraction equilibrium formula is described as follows:

[0089]

[0090] in: This represents the molar concentration of component A in the organic phase.

[0091] A represents the molar concentration of component A in the aqueous phase;

[0092] This represents the molar concentration of component B in the organic phase.

[0093] B represents the molar concentration of component B in the aqueous phase.

[0094] β A / B The extraction separation coefficient is denoted as .

[0095] The clarification chamber simulation calculation module is used to simulate and calculate the operating status of the clarification chamber based on initial variables and intermediate process variables.

[0096] The basic formulas used in the clarifier simulation calculation module include, but are not limited to, the two-phase pressure balance formula and the weir flow formula.

[0097] The two-phase pressure balance formula is described as follows:

[0098]

[0099] like Figure 7 As shown, where:

[0100] ρ o The density of the organic phase in the clarifier;

[0101] h o The height of the organic phase in the clarifier;

[0102] ρ a The density of the aqueous phase in the clarification chamber;

[0103] h a The water phase height in the clarifier;

[0104] H is the height of the water phase overflow weir;

[0105] H0 is the water head height above the water phase weir.

[0106] The weir flow type is a thin-walled weir, and the weir flow formula is described as follows:

[0107]

[0108] like Figure 8 As shown, where:

[0109] Q represents the weir flow rate of the aqueous or organic phase per unit time;

[0110] m is the weir flow coefficient, which ranges from 0 to 10 depending on the structure of the overflow weir.

[0111] B is the equivalent weir width;

[0112] g is the gravitational acceleration constant;

[0113] H0 is the water head height above the weir.

[0114] The iteration control module is used to control the minimum time unit and the number of iterations in the iterative calculation process. The minimum time unit ranges from 1 microsecond to 10 minutes. Since a numerical calculation method is used, each module needs to set a minimum time unit during the calculation process. The smaller the minimum time unit, the higher the calculation accuracy, but the longer the calculation time. The minimum time unit is set according to the actual required calculation accuracy.

[0115] The number of iterations can be set to a fixed value, or it can be set to automatically terminate after the key parameters of each mixing and clarification tank tend to stabilize. Key parameters include, but are not limited to, aqueous phase flow rate, organic phase flow rate, aqueous phase storage tank volume, organic phase storage tank volume, aqueous phase component concentration, and organic phase component concentration.

[0116] At time t=0, the external flow parameters change, with the organic flow rate increasing from 800 L / min to 1100 L / min, while the aqueous flow rate remains constant at 1000 L / min. Based on the simulation system and calculation method for the mixing and clarification tank provided by this invention, the parameters are input into the mixing chamber simulation calculation module and the clarification chamber simulation calculation module, and iterative calculations are performed under the control of the iterative control module. Finally, the equilibrium state data of this section of the mixing and clarification tank and the intermediate process data of the transition from a non-equilibrium state to an equilibrium state are obtained.

[0117] The simulation results show that:

[0118] (1) As Figure 9 As shown, starting from t=0, the effect of the change in the flow rate of the organic phase gradually propagates from the first stage to the 50th stage over time.

[0119] (2) Figure 10 As shown, starting from t=0, the change in the flow rate of the organic phase causes a change in the mixing chamber reservoir (relative change), which is the "filling" process of the mixing chamber commonly seen in engineering practice.

[0120] (3) Figure 11 As shown, due to the change in organic phase flow rate, the "filling" process in the mixing chamber will "squeeze out" more water phase, causing the water phase flow rate to increase rapidly in a short period of time, resulting in a peak water phase flow rate.

[0121] (4) Figure 9 and Figure 11 As shown, the flow rates of the organic and aqueous phases in the entire mixing and clarification tank exhibit a recurring "oscillation" pattern, with the oscillation amplitude gradually decreasing until it eventually approaches a new equilibrium state.

[0122] Verification has shown that the calculation results of the simulation system are in good agreement with engineering practice data.

[0123] Example 2

[0124] This invention provides a simulation calculation method for a mixing clarifier tank. The method is based on a simulation system for a mixing clarifier tank provided in Embodiment 1 and its optional embodiments. The method includes the following steps:

[0125] S1. Set the initial flow parameters and mixing and clarification tank equipment parameters. The single-stage tank of the mixing and clarification tank includes a mixing chamber and a clarification chamber. The aqueous phase and organic phase of the single-stage tank flow countercurrently between the stages of the tank.

[0126] S2. Set the changes in external flow parameters during the simulation process;

[0127] S3. Simulate and calculate the operating status of the mixing chamber based on the relevant data set in steps S1 and S2;

[0128] S4. Simulate and calculate the operating status of the clarification chamber based on the relevant data set in steps S1 and S2.

[0129] S5. Control the minimum time unit and number of iterations in the iterative calculation process to perform iterative calculations.

[0130] As can be seen from the above embodiments, the simulation system and calculation method for a mixing and clarification tank disclosed in this invention include an initial external variable input module, an intermediate process external variable input module, a mixing chamber simulation calculation module, a clarification chamber simulation calculation module, and an iterative control module. By setting initial flow parameters and mixing and clarification tank equipment parameters, and setting the changes in external flow parameters during the simulation process, the operating state of the mixing chamber and the clarification chamber are simulated and calculated based on the set initial flow parameters and relevant data of intermediate process external variables. The minimum time unit and number of iterations in the iterative calculation process are controlled for iterative calculation. Using the method disclosed in this invention, a simulation system for the liquid volume and flow rate of the mixing and clarification tank is constructed through numerical simulation, comprehensively applying multiple theoretical models such as pressure balance, weir flow model, extraction balance, and heterogeneous mixing process, providing reliable data support for the construction of an intelligent control system for rare earth extraction and separation.

[0131] The system and method described in this invention are not limited to the embodiments described in the specific implementation. Other implementation methods derived by those skilled in the art based on the technical solution of this invention also fall within the scope of technical innovation of this invention.

Claims

1. A simulation system for a mixing and clarification tank, characterized in that: The system includes an initial external variable input module for setting initial flow parameters and mixing and clarification tank equipment parameters. The single-stage tank of the mixing and clarification tank includes a mixing chamber and a clarification chamber. The aqueous phase and organic phase of the single-stage tank flow countercurrently between the stages of the tank. The intermediate process external variable input module is used to set the changes in external flow parameters during the simulation process; The mixing chamber simulation calculation module is used to simulate and calculate the operating status of the mixing chamber based on the relevant data in the initial external variable input module and the intermediate process external variable input module. The clarification chamber simulation calculation module is used to simulate and calculate the operating status of the clarification chamber based on the relevant data in the initial external variable input module and the intermediate process external variable input module. And an iteration control module, used to control the minimum time unit and number of iterations in the iterative calculation process for iterative computation; The basic formulas used by the mixing chamber simulation calculation module for simulation calculations include the heterogeneous mixing process formula and the extraction equilibrium formula. The formula for the heterogeneous mixing process is described as follows: Where: γ(t) is the ratio of organic phase volume to aqueous phase volume at time t; γ(t+1) represents the ratio of organic phase volume to aqueous phase volume at time t+1; γ F The ratio of the flow rate of the organic phase to the flow rate of the aqueous phase in the feed solution; F represents the total feed flow rate; V represents the total volume of the storage tank; An extraction separation system containing two components, A and B, is described by the extraction equilibrium formula as follows: in: This represents the molar concentration of component A in the organic phase. A represents the molar concentration of component A in the aqueous phase; This represents the molar concentration of component B in the organic phase. B represents the molar concentration of component B in the aqueous phase. β A / B The extraction separation coefficient is denoted as .

2. The simulation system for a mixing and clarification tank as described in claim 1, characterized in that: The initial flow parameters include the initial flow rate of the organic phase and the initial flow rate of the aqueous phase entering the mixing and clarification tank from the outside.

3. The simulation system for a mixing and clarification tank as described in claim 1, characterized in that: The parameters of the mixing and clarification tank equipment include the total number of tank stages, mixing chamber volume, initial mixing chamber ratio, clarification chamber volume, organic phase overflow weir height in the clarification chamber, aqueous phase overflow weir height in the clarification chamber, equivalent organic phase overflow weir width in the clarification chamber, and equivalent aqueous phase overflow weir width in the clarification chamber.

4. The simulation system for a mixing and clarifying tank as described in claim 1, characterized in that: The external flow parameters include the flow rates of the organic phase and the aqueous phase entering the mixing and clarification tank from the outside during the simulation process.

5. The simulation system for a mixing and clarification tank as described in claim 1, characterized in that: The basic formulas used in the clarification chamber simulation calculation module include the two-phase pressure balance formula and the weir flow formula. The two-phase pressure balance formula is described as follows: Where: ρ o The density of the organic phase in the clarifier; h o The height of the organic phase in the clarifier; ρ a The density of the aqueous phase in the clarification chamber; h a The water phase height in the clarifier; H is the height of the water phase overflow weir; H0 is the water head height above the water phase weir.

6. The simulation system for a mixing and clarification tank as described in claim 5, characterized in that: The weir flow type is a thin-walled weir, and the weir flow formula is described as follows: in: Q represents the weir flow rate of the aqueous or organic phase per unit time; m is the weir flow coefficient, which ranges from 0 to 10 depending on the structure of the overflow weir. B is the equivalent weir width; g is the gravitational acceleration constant; H0 is the water head height above the weir.

7. A simulation calculation method for a mixing clarifier, said method being based on a simulation system for a mixing clarifier as described in any one of claims 1-6, said method comprising the following steps: S1. Set the initial flow parameters and mixing and clarification tank equipment parameters. The single-stage tank of the mixing and clarification tank includes a mixing chamber and a clarification chamber. The aqueous phase and organic phase of the single-stage tank flow countercurrently between the stages of the tank. S2. Set the changes in external flow parameters during the simulation process; S3. Simulate and calculate the operating status of the mixing chamber based on the relevant data set in steps S1 and S2; S4. Simulate and calculate the operating status of the clarification chamber based on the relevant data set in steps S1 and S2. S5. Control the minimum time unit and number of iterations in the iterative calculation process to perform iterative calculations.

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