UF6 rectification process model based on HSC-Aspen combination method and application thereof
The HSC-Aspen combined method supplements the physical properties parameters of UF6 and other impurities, solves the problem of missing UF6 distillation data in the prior art, improves the simulation accuracy, and achieves efficient purification of UF6.
Patent Information
- Application Number
- CN202411601808.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-11
- Publication Date
- 2025-02-18
AI Technical Summary
The lack of vapor-liquid phase equilibrium data and related physical properties of UF6 and other impurities in the prior art has caused the simulation results of the UF6 distillation process inconsistent with the pilot results, and even serious deviations are caused.
Using the HSC-Aspen combined method, the missing physical parameters in Aspen are supplemented by HSC, and the missing parameters are supplemented by the constant estimation system based on known data. The liquid saturated vapor pressure and pure of the distillation system are obtained through Aspen's expansion equation and estimation system. Component saturated vapor pressure.
It effectively solved the result distortion problem caused by the missing data of UF6 distillation, and improved the simulation accuracy of the UF6 distillation process. The UF6 recovery rate reached 98.28%, and the UF6 molar fraction rate increased from 98.8% to 99.8%, achieving UF6 purification.
Smart Images
Figure CN119479849A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a UF6 distillation process model, in particular to a UF6 distillation process model based on a HSC-Aspen combined method and application thereof, belonging to the technical field of uranium purification and conversion. Background Art
[0002] In the existing technology, due to the lack of vapor-liquid equilibrium data and physical property data of uranium hexafluoride and fluorides, it is difficult to carry out modeling and simulation of the uranium hexafluoride purification distillation process. However, the modeling and simulation of the distillation process can provide key technical and data support for the design and optimization of pilot and industrial equipment. In order to solve the above problems, many scientific research groups have adopted the following methods: China University of Petroleum used COSMOtherm and Turbomole software to predict the vapor-liquid equilibrium data of the binary system of UF6 and TiF4, and used the physical property constant estimation system of Aspen Plus software to estimate the missing physical parameters such as the Gibbs formation energy of infinite dilution aqueous solution. The experimental data of UF6 saturated vapor pressure were compared with the simulated values, and the relative error was within 1.76%; Tianjin University summarized various methods of molecular simulation to calculate the thermodynamic properties of substances, systematically introduced the development of different force fields and potential energy functions in simulation calculations and their advantages and disadvantages, pointed out the applicability to fluoride systems, and further, used quantum chemistry theory to simulate the thermodynamic properties of fluorides, optimized the molecular configuration of related fluorides, and improved the accuracy of simulation calculations.
[0003] However, although the above methods have improved the simulation accuracy of the UF6 distillation purification and separation process, the current problem in this process is the lack of vapor-liquid equilibrium data of UF6 and other impurity materials, such as MoF6, VF5 and WF6, as well as other related physical property data such as critical pressure, which leads to the simulation results being inconsistent with the pilot results, and even causing serious deviations. Summary of the invention
[0004] In view of the problems existing in the prior art, the first object of the present invention is to provide a UF6 distillation process model based on the HSC-Aspen joint method. The model realizes the simulation of the distillation process of uranium dry purification and conversion into uranium hexafluoride through the HSC-Aspen joint method, supplements some missing physical property parameters in Aspen through HSC, and then supplements the remaining missing pure component physical property parameter estimates of UF6, VF5, MoF6 and WF6 according to the known normal boiling point and molecular weight through the constant estimation system, and then obtains the liquid saturated vapor pressure and the pure component saturated vapor pressure in the distillation system through the extended equation Antoine and the estimation system in Aspen, effectively solving the technical problem of distorted results caused by the missing uranium hexafluoride distillation data in the prior art.
[0005] The second object of the present invention is to provide an application of the UF6 distillation process model based on the HSC-Aspen combined method, which is used for the design of pilot distillation parameters for uranium dry purification and conversion of uranium hexafluoride. Based on the excellent accuracy and authenticity of the above-mentioned combined method uranium hexafluoride distillation process model, the present invention is used for the design of pilot distillation parameters for uranium dry purification and conversion of uranium hexafluoride. The pilot experiment was carried out using the optimized distillation parameters, and the UF6 recovery rate reached 98.28%, and the UF6 mole fraction was increased from 98.8% to 99.8%, achieving the purification of UF6.
[0006] In order to achieve the above technical objectives, the present invention provides a UF6 distillation process model based on the HSC-Aspen combined method, comprising:
[0007] Step S1, inputting UF6, HF, F2, MoF6, WF6 and VF5 groups into Aspen software and HSC software respectively, and combining with the estimation system to obtain the basic physical property constants of each component;
[0008] Step S2, fitting binary vapor-liquid equilibrium data of UF6-MoF6, UF6-WF6 and UF6-VF5 according to the NRTL model and the basic physical property constants obtained in step S1;
[0009] Step S3, establishing a simple calculation model for UF6 distillation according to the DSTWU model and the vapor-liquid equilibrium data obtained in step S2, and determining the distillation process parameters;
[0010] Step S4: establishing a strict calculation model for distillation according to the distillation process parameters and distillation hydraulics obtained in step S3.
[0011] As a preferred solution, the basic physical property constants include: molecular weight, boiling point, critical constant, eccentricity factor, saturated vapor pressure, heat capacity coefficient and Gibbs formation energy.
[0012] As a preferred solution, the simplified calculation model for distillation includes a UF6 purification distillation model; the purification distillation model includes 1 to 3 distillation columns, a low boiling tower and a high boiling tower.
[0013] As a preferred scheme, the distillation process of the purification distillation model is as follows: the crude UF6 raw material passes through a flash tank and enters a low-boiling tower to remove light component fluoride impurities, and the purified UF6 then passes through a high-boiling tower in turn to remove heavy component fluoride impurities, and the refined UF6 enters a condenser to obtain the product.
[0014] As a preferred solution, the initial boundary conditions of the distillation column are: the initial boundary input conditions of the distillation column are the molar composition of the raw materials and the basic physical property parameters of each component.
[0015] As a preferred solution, the process of determining the distillation process parameters is as follows: the simulation results of the UF6 purification distillation model are added with the tower design regulations through the distillation tower strict calculation module RadFrac, and then sensitivity analysis is performed to obtain the result.
[0016] As a preferred solution, the distillation process parameters include the optimal number of plates, feed position and reflux ratio.
[0017] As a preferred solution, the process of establishing the strict calculation model of distillation is: using the distillation process parameters obtained in step S3 as parameter input, and calculating the tower type, tower component parameters, parameters of each stream and tower operation parameters through distillation hydraulics.
[0018] As a preferred solution, the implementation process of the distillation hydraulics is: using the hydraulic module in Aspen to perform hydraulic calculations, and using Cuptower to verify the hydraulic data obtained by Aspen.
[0019] As a preferred solution, the specific process of distillation hydraulics is: select the report option under analysis in the tower module, check include hydraulic parameters on the property options page, and click hydraulic in the profile to view it.
[0020] As a preferred solution, the tower component parameters mainly include: tower inner diameter, height between tower plates and overflow weir parameters.
[0021] As a preferred solution, the process of the sensitivity analysis is: inputting relevant independent variables and dependent variables in the Seneitivity module of Model Analysis Tools, obtaining the correlation relationship between the number of plates and the dependent variables, and obtaining the optimal condition.
[0022] As a preferred solution, the independent variables include theoretical plate number, reflux ratio and feed position.
[0023] As a preferred solution, the dependent variables include parameters such as the molar fraction of the tower top and tower bottom products, and the heat load of the reboiler and condenser.
[0024] The present invention also provides an application of the UF6 distillation process model based on the HSC-Aspen combined method as described in any one of the above, which is used for the design of distillation pilot parameters for uranium dry purification and conversion of uranium hexafluoride.
[0025] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:
[0026] 1) The present invention realizes the simulation of the distillation process of uranium dry purification and conversion of uranium hexafluoride through the HSC-Aspen joint method, supplements some missing physical property parameters in Aspen through HSC, and then supplements the remaining missing pure component physical property parameter estimates of UF6, VF5, MoF6 and WF6 according to the known normal boiling point and molecular weight through the constant estimation system, and then obtains the saturated vapor pressure of the liquid in the distillation system and the saturated vapor pressure of the pure component through the extended equation Antoine and the estimation system in Aspen, effectively solving the technical problem of distorted results caused by missing uranium hexafluoride distillation data in the prior art.
[0027] 2) In the technical solution provided by the present invention, based on the excellent accuracy and authenticity of the combined method uranium hexafluoride distillation process model, it is used for the design of pilot parameters for uranium dry purification and conversion of uranium hexafluoride distillation. The pilot experiment was carried out using the optimized distillation parameters, and the UF6 recovery rate reached 98.28%, and the UF6 molar fraction was increased from 98.8% to 99.8%, thereby achieving the purification of UF6. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 This is a schematic diagram of the uranium hexafluoride distillation process provided by the present invention;
[0029] Figure 2 A schematic diagram of distillation tray parameters provided by the present invention;
[0030] Figure 3 This is a schematic diagram of the distillation hydraulic calculation parameters provided by the present invention. DETAILED DESCRIPTION
[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative ideas are within the scope of protection of the present invention.
[0032] Example 1
[0033] This embodiment provides a UF6 distillation process model based on the HSC-Aspen combined method, and the specific process is as follows:
[0034] 1) Physical property input
[0035] Input UF6 and HF, F2, MoF6, WF6, VF5 components. For non-database components, fill in the saturated vapor pressure of pure components in the estimation system. The Gibbs formation energy, entropy at 25℃ and heat capacity coefficient in the estimation system use the data in the HSC software. The results are shown in Table 1.
[0036] 2) Method determination
[0037] The NRTL model was selected by Aspen plus V8.1 software to fit the binary vapor-liquid equilibrium data of UF6-MoF6, UF6-WF6 and UF6-VF5. The binary interaction parameters obtained are shown in Table 2.
[0038] 3) Establish a simple calculation module for distillation
[0039] First, establish a uranium hexafluoride purification distillation model. The uranium hexafluoride distillation system consists of a low-boiling tower and a high-boiling tower. Select a distillation tower from the Aspen operating unit library, connect the logistics, and establish a distillation module. The process flow is as follows: Figure 1 The main function of the low-boiling tower is to remove impurity fluorides with a lower boiling point than uranium hexafluoride. The crude uranium hexafluoride raw material first enters the low-boiling tower and then enters the high-boiling tower after being distilled out of the tower bottom.
[0040] The initial boundary conditions were set to simulate the molar fraction of uranium hexafluoride in the feed liquid to be 98.8%; the molar fraction of the heavy component, calculated as impurity fluoride, was 0.3%; the molar fraction of the light component was 0.9%. The specific feed logistics data are shown in Table 3. The low-boiling column has a diameter of 0.61m, a column height of about 28.8m, 100 bubble cap plates, and an operating temperature of about 45°C. The light fraction coming out of the first low-boiling tower is sent to the waste recovery system to recover uranium; the heavy fraction is sent to a high-boiling tower with 50 plates. The light fraction coming out of the high-boiling tower is purified UF6, which is sent to the condenser to collect UF6. The heavy fraction is enriched with impurities with lower volatility than uranium hexafluoride and is sent to the waste recovery system to recover uranium. The feed rate of the low boiling tower is 40 kmol / h; the operating pressure of the tower is 0.703 MPa; the number of plates is 100; the feed position is on the 48th plate; and the operating temperature is 45°C. The operating pressure of the high boiling tower is 0.668 MPa; the number of plates is 50; the operating temperature is 50°C; and the feed position is on the 5th plate.
[0041] First, the simple design module DSTWU is used for simple design. The calculation results provide initial values for strict distillation calculation. Then, the tower design regulations are added through the distillation tower strict calculation module RadFrac. The sensitivity analysis is used to determine the optimal number of tower plates, feed position and reflux ratio. The preliminary tower design parameters are shown in Table 4.
[0042] 4) Establish a rigorous calculation module for distillation
[0043] Strict calculations are performed based on the results of the simple calculation module, with the main calculation objects being tower type, tower component parameters, parameters of each stream, tower operating parameters, etc.
[0044] Input the parameters obtained by simple calculation to prepare for strict calculation. The tower internals are plate towers, and the tower plates are sieve plate towers. The main design parameters of the tower internals include the inner diameter of the tower, the height between the tower plates, the overflow weir parameters, etc. The above parameters need to be adjusted repeatedly to meet the design requirements. For specific situations, refer to the hydraulic operation diagram to make the operation diagram within the operation line. Through hydraulic operation calculation, the results are as follows Figure 3 As shown, it is proved that the tower plate setting can meet the requirements.
[0045] It can be seen from Table 5 that after strict distillation calculation, the UF6 recovery rate reached 98.28%, and the UF6 molar fraction increased from 98.8% to 99.8%, achieving the purification of UF6.
[0046] Sensitivity analysis was used to optimize the key parameters of the number of plates, feed position and reflux ratio, and the final tower design parameters are shown in Table 6.
[0047]
[0048]
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[0050]
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Claims
1. A UF6 distillation process model based on the HSC-Aspen combined method, characterized in that: include: Step S1, inputting UF6, HF, F2, MoF6, WF6 and VF5 groups into Aspen software and HSC software respectively, and combining with the estimation system to obtain the basic physical property constants of each component; Step S2, fitting binary vapor-liquid equilibrium data of UF6-MoF6, UF6-WF6 and UF6-VF5 according to the NRTL model and the basic physical property constants obtained in step S1; Step S3, establishing a simple calculation model for UF6 distillation according to the DSTWU model and the vapor-liquid equilibrium data obtained in step S2, and determining the distillation process parameters; Step S4: establishing a strict calculation model for distillation according to the distillation process parameters and distillation hydraulics obtained in step S3.
2. The UF6 distillation process model based on the HSC-Aspen combined method according to claim 1, characterized in that: The basic physical property constants include: molecular weight, boiling point, critical constant, eccentricity factor, saturated vapor pressure, heat capacity coefficient and Gibbs formation energy.
3. The UF6 distillation process model based on the HSC-Aspen combined method according to claim 1 is characterized in that: The simple calculation model for distillation includes a UF6 purification distillation model; the purification distillation model includes a flash tank, a low boiling tower and a high boiling tower.
4. The UF6 distillation process model based on the HSC-Aspen combined method according to claim 3 is characterized in that: The distillation process of the purification distillation model is as follows: the crude UF6 raw material passes through a flash tank and enters a low-boiling tower to remove light component fluoride impurities. The purified UF6 then passes through a high-boiling tower to remove heavy component fluoride impurities. The refined UF6 enters a condenser to obtain the product.
5. The UF6 distillation process model based on the HSC-Aspen combined method according to claim 4 is characterized in that: The initial boundary input conditions of the distillation column are the molar composition of the raw materials and the basic physical property parameters of each component.
6. The UF6 distillation process model based on the HSC-Aspen combined method according to claim 4 is characterized in that: The process of determining the distillation process parameters is as follows: the simulation results of the UF6 purification distillation model are added with the tower design regulations through the distillation tower strict calculation module RadFrac, and then sensitivity analysis is performed to obtain the result.
7. The UF6 distillation process model based on the HSC-Aspen combined method according to claim 1 is characterized in that: The distillation process parameters include the optimal number of plates, feed position and reflux ratio.
8. The UF6 distillation process model based on the HSC-Aspen combined method according to claim 1, characterized in that: The process of establishing the strict calculation model of distillation is as follows: using the distillation process parameters obtained in step S3 as parameter input, calculating the tower type, tower component parameters, parameters of each stream and tower operation parameters through distillation hydraulics; the tower component parameters mainly include: tower inner diameter, height between tower plates and overflow weir parameters.
9. The UF6 distillation process model based on the HSC-Aspen combined method according to claim 6, characterized in that: The process of the sensitivity analysis is as follows: inputting relevant independent variables and dependent variables into the Seneitivity module of Model Analysis Tools, obtaining the correlation relationship between the number of plates and the dependent variables, and obtaining the optimal conditions; The independent variables include the theoretical plate number, reflux ratio and feed position; the dependent variables include the molar fraction of the product in the tower top and bottom, the heat load of the reboiler and condenser and other parameters.
10. The application of the UF6 distillation process model based on the HSC-Aspen combined method according to any one of claims 1 to 9, characterized in that: Design of pilot distillation parameters for uranium dry purification and conversion of uranium hexafluoride.