A large industrial grade natural uranium extraction column modeling simulation method

Abstract

The present application relates to a kind of large-scale industrial grade natural uranium extraction column modeling simulation method.Establish the mass transfer diffusion model of pulse baffle extraction column, establish the thermodynamic model of uranyl nitrate extraction process, establish the hydraulics model of pulse baffle extraction column, the thermodynamic model of uranyl nitrate extraction process and the hydraulics model of pulse baffle extraction column are combined, mass transfer diffusion model is solved using Runge-Kutta method, i.e., the uranyl nitrate concentration result of outlet water phase and organic phase of pulse baffle extraction column can be calculated;The calculation result is checked, the final calculation result is obtained for the output meeting the requirements, and the calculation is returned again for the output not meeting the requirements.The present application can simulate the extraction process of uranyl nitrate with concentration up to 450g / L in industrial pulse baffle column, the simulation result has high precision, and the error between simulation result and measured value of uranyl nitrate extracted by real pulse baffle extraction column is within 8%.

Description

TECHNICAL FIELD

[0001] The present application relates to a large-scale industrial grade natural uranium extraction column modeling simulation method, in particular to a modeling and simulation method of an extraction column in a natural uranium hydrometallurgy process, which can be applied to an industrial grade pulse baffle plate extraction column with a diameter of up to 850 mm. BACKGROUND

[0002] Solvent extraction is an important chemical separation technology, which is realized by using the large difference in distribution coefficient of solute in two mutually insoluble or slightly soluble solvents, and is widely used in hydrometallurgy, petroleum chemical industry, food and drug separation industries. The extraction equipment mainly includes mixing clarifier, centrifugal extractor, pulse column and the like. The pulse extraction column is an extraction equipment with energy pulse input. Through pulse energy, the dispersed phase is broken and dispersed, the contact surface of two phases is increased, the turbulence of two phases is increased, the two phases are fully mixed, the rapid separation of two phases is facilitated, and the mass transfer of two phases is promoted. The annular baffle plate pulse column is gradually developed in the 1970s. Compared with the clarifying mixer, it has the advantages of simple structure, easy pollution removal, large flux and easy maintenance. Compared with the sieve plate and nozzle plate pulse column, the baffle plate pulse column has a wider operation zone, which is beneficial to the normal and stable operation of the equipment. Since the baffle plate pulse column has a large free cross-sectional area, it can handle the liquid containing solid particles, and meets the requirements of natural uranium extraction purification.

[0003] In the early stage, due to the immaturity of computer and software technology, the simulation and calculation research on the baffle plate pulse extraction column is less. So far, there is no simulation and simulation technology that can accurately reproduce the actual operation of the baffle plate pulse extraction column through software.

[0004] The present application provides a large-scale industrial grade natural uranium extraction column modeling simulation method, which can simulate the extraction process of nitric uranyl with a concentration of up to 450 g / L in an industrial grade pulse baffle plate column. The simulation result has high precision, and the error between the simulation result and the measured value of the actual pulse baffle plate extraction column extracting nitric uranyl is within 8%. The simulation software established by the method can be used to optimize the operation parameters of the pulse extraction column and train the process knowledge of the operating personnel. SUMMARY

[0005] The present application provides a large-scale industrial grade natural uranium extraction column modeling simulation method, which can simulate the extraction process of nitric uranyl with a concentration of up to 450 g / L in an industrial grade pulse baffle plate column. The simulation result has high precision, and the error between the simulation result and the measured value of the actual pulse baffle plate extraction column extracting nitric uranyl is within 8%. The simulation software established by the method can be used to optimize the operation parameters of the pulse extraction column and train the process knowledge of the operating personnel.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is:

[0007] A large industrial grade natural uranium extraction column modeling simulation method,

[0008] 1) Establish the mass transfer diffusion model of the pulse baffle plate extraction column:

[0009]

[0010]

[0011] Wherein, E x : Diffusion coefficient of dispersed phase; c x : Dispersed phase concentration; z: Column height; U x : Dispersed phase flow rate; k ox : Total mass transfer coefficient of dispersed phase; α: Mass transfer coefficient; c x * : Dispersed phase concentration in equilibrium with continuous phase; E y : Continuous phase diffusion coefficient; c y : Continuous phase concentration; U y : Continuous phase flow rate;

[0012] 2) Based on the thermodynamic model of the uranyl nitrate extraction process and the hydraulic model of the pulse baffle plate extraction column, the mass transfer diffusion model is solved;

[0013] 3) Establish the thermodynamic model of the uranyl nitrate extraction process:

[0014]

[0015] Wherein, [U] ORG : Uranyl nitrate concentration in extraction solution, gU / L; [TBP] AQ : TBP volume percentage in extractant, [NO3] AQ : Nitric acid concentration in raw solution, mol / L; [U] AQ : Uranyl nitrate concentration in raw solution, gU / L; T- Uranyl nitrate extraction process temperature, K;

[0016] 4) Establish the hydraulic model of the pulse baffle plate extraction column, and the dispersed phase holdup model structure is as follows:

[0017] Wherein: xd- Dispersed phase holdup; Af- Pulse intensity of pulse baffle plate extraction column, m / s; v d - Dispersed phase velocity, m / s; v c - Continuous phase velocity, m / s; △ρ- Density difference between dispersed phase and continuous phase, kg / m 3 ; ρd ——Dispersed phase density, kg / m 3 ρ c ——continuous phase density, kg / m 3 ;μ d ——Viscosity of dispersed phase, Pas; μ c ——Continuous phase viscosity, Pas; α——Pulse baffle extraction column annular void ratio; γ——Dispersed phase surface tension, N / m; (Af) m ——Average pulse intensity of pulse baffle extraction column, m / s; g-gravitational acceleration, kg / N;

[0018] 5) Combining the thermodynamic model of the uranyl nitrate extraction process with the hydraulic model of the pulse baffle extraction column, and solving the mass transfer and diffusion model using the Jung-Kutta method, the uranyl nitrate concentrations at the aqueous and organic phase outlets of the pulse baffle extraction column can be calculated;

[0019] 6) Verify the calculation results, obtain the final calculation results for the outputs that meet the requirements, and return to recalculate for those that do not meet the requirements.

[0020] The mass transfer and diffusion model of the pulse baffle extraction column was established by differential method.

[0021] The mass transfer and diffusion model of the pulse baffle extraction column was dimensionless.

[0022] By conducting uranyl nitrate extraction equilibrium experiments, the thermodynamic equilibrium data of uranyl nitrate were obtained, the thermodynamic equilibrium equation of uranyl nitrate was established, and the thermodynamic model of the uranyl nitrate extraction process was established through planning and solving.

[0023] The thermodynamic model of the uranyl nitrate extraction process is applicable to the uranyl nitrate extraction process in the concentration range of 1g / L-450g / L.

[0024] The beneficial effects achieved by the present invention are:

[0025] 1) This method can simulate the extraction operation results of a large baffled pulse extraction column in the "wet" purification process of natural uranium in the natural uranium cycle. The modeling method is accurate and highly precise, and the error between the actual pulse baffled extraction column and the measured value of uranyl nitrate extraction is within 8%.

[0026] 2) The model established by this method can calculate the extraction rate and uranium concentration of the residual liquid and the uranium concentration of the organic phase under different conditions. These parameters can be used to intuitively see the operation status of the extraction column and whether the discharged residual liquid meets the standards. This has certain guiding significance for the operation of the extraction column, optimizing parameters, and finding the cause of failure.

[0027] 3) The method first realizes the simulation of the extraction process of the large baffle plate pulse extraction column in the natural uranium "wet" purification process in the country, has high accuracy and is at the leading level in the country. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The mass balance diagram of the diffusion model. DETAILED DESCRIPTION

[0029] The application will be described in detail below in combination with the drawings and specific embodiments.

[0030] The application provides a modeling and simulation method of an extraction column in a natural uranium "wet" purification process. The specific modeling process is as follows:

[0031] 1) For the pulse extraction column, first, based on mass balance, the mass transfer and diffusion model of the pulse baffle plate extraction column is established by differential method, and the specific mass balance can be expressed as shown in the formula (1): Figure 1 As shown in the formula (1), wherein,

[0032] Feed: feed solution, Raffinate: raffinate water, Solvent: extractant, Extract: extract

[0033] X-Phase: dispersed phase; Y-Phase: continuous phase;

[0034] U x : dispersed phase flow rate; U y : continuous phase flow rate;

[0035] c x : dispersed phase concentration; c y : continuous phase concentration; c x * : dispersed phase concentration in equilibrium with the continuous phase;

[0036] E x : diffusion coefficient of the dispersed phase; E y : continuous phase diffusion coefficient;

[0037] k ox : total mass transfer coefficient of the dispersed phase;

[0038] z: column height; δ: mass transfer differential height; α: mass transfer coefficient.

[0039] Through mass balance calculation on one of the mass transfer differential heights, the following results can be obtained:

[0040]

[0041]

[0042] 2) The mass transfer diffusion model of the pulse baffle plate extraction column is established by combining formula 1.1 with 1.2, and is dimensionless, forming the final mass transfer model.

[0043] 3) Then, based on the mass transfer model, the present application proposes that the solution of the mass transfer model is based on the combination of the thermodynamic model of the uranyl nitrate extraction process and the hydrodynamic model of the pulse baffle plate extraction column, instead of the traditional single thermodynamic model theoretical solution calculation. This method can organically combine the theoretical model of the extraction process with the structural model of the pulse extraction column, establish the model of the industrial pulse extraction column, so as to realize the modeling and solving of the uranyl nitrate extraction process of the whole pulse baffle plate extraction column, and effectively improve the accuracy.

[0044] 3) Next, the thermodynamic model of the uranyl nitrate extraction process is established. Through the uranyl nitrate extraction equilibrium experiment, the thermodynamic equilibrium data of uranyl nitrate is obtained, the thermodynamic equilibrium equation of uranyl nitrate is established, and the establishment of the thermodynamic model of the uranyl nitrate extraction process is realized through programming solution. The model is unique to this patent, and is suitable for the concentration range of 1g / L-450g / L uranyl nitrate extraction process, and the specific model is as follows:

[0045]

[0046] Wherein, [U] ORG - the concentration of uranyl nitrate in the extraction solution, gU / L; [TBP] AQ - the volume percentage of TBP in the extractant, [NO3] AQ - the nitric acid concentration in the raffinate, mol / L; [U] AQ - the concentration of uranyl nitrate in the raffinate, gU / L; T - the temperature of the uranyl nitrate extraction process, K.

[0047] 4) The hydrodynamic model of the pulse baffle plate column is established. In the process of establishing the hydrodynamic model, in order to ensure that the model is more suitable for the structure of the baffle plate column, the hydrodynamic model is optimized in this patent, and the model is unique to this patent, wherein the structure of the dispersed phase holdup model is as follows:

[0048] Wherein: xd - dispersed phase holdup; Af - pulse intensity of the pulse baffle plate extraction column, m / s; v d - dispersed phase velocity, m / s; v c - continuous phase velocity, m / s; △ρ - density difference between the dispersed phase and the continuous phase, kg / m 3 ; ρ d - dispersed phase density, kg / m 3 ; ρc Continuous phase density, kg / m 3 ; μ d Dispersed phase viscosity, Pas; μ c Continuous phase viscosity, Pas; α - Pulse baffle extraction column annulus ratio; γ - Dispersed phase surface tension, N / m; (Af) m Pulse baffle extraction column average pulse intensity, m / s; g - Gravitational acceleration, kg / N.

[0049] 5) After the completion of the thermodynamic model of the uranyl nitrate extraction process and the hydraulic model of the pulse baffle extraction column, the two are combined, and the mass transfer model (i.e. Equations 1.1 and 1.2) is solved using the Runge-Kutta method, which can calculate the uranyl nitrate concentration results of the water phase and organic phase outlet of the pulse baffle extraction column.

[0050] 6) After the completion of the operation calculation, the calculation results are checked, and the final calculation results are obtained for the output that meets the requirements, and the calculation is returned to the model calculation unit for re-calculation for the output that does not meet the requirements.

[0051] A variety of mathematical models of fluid flow, droplet size and distribution, axial mixing, and interfacial mass transfer in the baffle extraction column were used to establish a mathematical model of the purification of uranyl nitrate solution, and the mathematical model was made into an extraction column calculation software. The software is written based on VBA language and can be applied to the simulation calculation of different acidity, different temperature, and different TBP content of the extraction column. The extraction column diagram is designed and drawn, and its embedding in Excel Spreadsheet is realized, and it is made into the interface of the extraction simulation software. At the same time, the following functions are set: the input of the concentration, flow rate, and acidity of the water phase inlet solution (extraction feed) of the extraction column; the input of the concentration, flow rate, and TBP content of the organic phase inlet solution (extractant) of the extraction column; the input of the pulse amplitude and pulse frequency; the output of the concentration of the water phase outlet solution (extraction residue) of the extraction column and the extraction rate; the output of the concentration of the organic phase outlet solution of the extraction column and the extraction rate. The interface contains the extraction equilibrium curve and the observation interface of the uranium concentration distribution diagram of the extraction column.

Claims

1. A large-scale industrial-grade natural uranium extraction column modeling and simulation method, characterized by: 1) Establish a mass transfer and diffusion model for the pulse baffle extraction column: Among them, E x : diffusion coefficient of the dispersed phase; c x : dispersed phase concentration; z: column height; U x : dispersed phase flow rate; k ox : total mass transfer coefficient of dispersed phase; α: mass transfer coefficient; c x * : Concentration of the dispersed phase in equilibrium with the continuous phase; E y : continuous phase diffusion coefficient; c y : continuous phase concentration; U y : continuous phase flow rate; 2) Solve the mass transfer and diffusion model based on the thermodynamic model of the uranyl nitrate extraction process and the hydraulic model of the pulse baffle extraction column; 3) Establish a thermodynamic model for the uranyl nitrate extraction process: Among them, [U] ORG ——Concentration of uranyl nitrate in the extract, gU / L; [TBP] AQ ——The volume percentage of TBP in the extractant, [NO3] AQ ——nitric acidity in the extraction solution, mol / L; [U] AQ ——Uranyl nitrate concentration in the extraction solution, gU / L; T——Uranyl nitrate extraction process temperature, K; 4) Establish a hydraulic model for the pulse baffle extraction column. The dispersed phase holdup model structure is as follows: Where: xd - dispersed phase holdup; Af - pulse intensity of pulse baffle extraction column, m / s; v d ——dispersed phase velocity, m / s; v c ——continuous phase velocity, m / s; △ρ——density difference between dispersed phase and continuous phase, kg / m 3 ρ d ——Dispersed phase density, kg / m 3 ρ c ——continuous phase density, kg / m 3 ;μ d ——Viscosity of dispersed phase, Pas; μ c ——Continuous phase viscosity, Pas; α——Pulse baffle extraction column annular void ratio; γ——Dispersed phase surface tension, N / m; (Af) m ——Average pulse intensity of pulse baffle extraction column, m / s; g-gravitational acceleration, kg / N; 5) The thermodynamic model of the uranyl nitrate extraction process and the hydraulic model of the pulse baffle extraction column were combined, and the mass transfer and diffusion model was solved using the Jung-Kutta method to calculate the uranyl nitrate concentration results at the aqueous and organic phase outlets of the pulse baffle extraction column; 6) Verify the calculation results, obtain the final calculation results for the outputs that meet the requirements, and return to recalculate for those that do not meet the requirements.

2. The large-scale industrial-grade natural uranium extraction column modeling and simulation method according to claim 1, characterized in that: The mass transfer and diffusion model of the pulse baffle extraction column was established by differential method.

3. The large-scale industrial-grade natural uranium extraction column modeling and simulation method according to claim 1 is characterized in that: The mass transfer and diffusion model of the established pulse baffle extraction column was dimensionless.

4. The large-scale industrial-grade natural uranium extraction column modeling and simulation method according to claim 1 is characterized in that: By conducting uranyl nitrate extraction equilibrium experiments, the thermodynamic equilibrium data of uranyl nitrate were obtained, the thermodynamic equilibrium equation of uranyl nitrate was established, and the thermodynamic model of the uranyl nitrate extraction process was established through planning and solving.

5. The large-scale industrial-grade natural uranium extraction column modeling and simulation method according to claim 1 is characterized in that: The thermodynamic model of the uranyl nitrate extraction process is applicable to the uranyl nitrate extraction process in the concentration range of 1g / L-450g / L.

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