萃取槽前室结构研究

发布时间：2018-09-02 06:41

【摘要】：在冶金、医药等许多工业领域中萃取槽的结构不断得到改进,继简单箱式混合澄清器以后出现了EC-D型萃取槽、双混合室萃取槽和双搅拌澄清萃取槽等具有较高混合效率和澄清效率的萃取槽。但是,国内外学者对萃取槽结构的研究多集中在对混合室和澄清室的优化,对前室的研究非常少。前室是位于混合室正下方的长方体空腔,对进入混合室的物料起到缓冲作用,同时能够增加重相和轻相的接触时间,提高混合效率。本文利用FLUENT软件模拟分析不同前室结构对搅拌桨抽吸力,混合室内两相混合速率和混合效率的影响。所做的工作如下:以四种前室结构下的萃取槽混合室为研究对象,模拟料液和P507在不断流入和流出混合室的条件下的搅拌混合过程,以搅拌桨抽吸力、混合速率和单位体积混合能为评价指标,求解四种前室结构的混合室内部速度场、压力场和浓度场,分析前室结构对混合过程的影响。隔板式混合室混合效果最差,搅拌桨的抽吸力最小,物料被抽入混合室的速度最小;管式混合室混合速率最大,单位体积混合能最小,搅拌桨的抽吸力最大,混合效果最好;无隔板式混合室混合效果次之。混合效果和萃取槽改造成本综合考虑,企业将隔板式萃取槽改为无隔板式萃取槽,取得了较好的试验效果。但是试验中发现:搅拌桨插入深度过低,使前室内物料随搅拌桨旋转,不利于物料的抽吸;重相入口压力较大时水会反串入有机相管道;通过90°弯管连接的两级萃取槽内被抽吸的物料流量非常小。本文针对所发现的问题对无隔板式萃取槽进一步改进,通过数值模拟和实验结合的方法确定搅拌桨的最佳插入深度、两级管路连接类型改为椭圆管。管式萃取槽由于目前企业改造成本的原因没有选用,研究表明它仍然是萃取槽前室的最佳结构,本文进一步对其结构尺寸进行选优。以抽吸力和搅拌功率为评价指标,求解两相物料混合的速度场,得出搅拌桨的最佳插入深度、抽吸孔径值和搅拌转速,使搅拌桨功率损耗较低的同时抽吸力最大。
[Abstract]:In many industrial fields such as metallurgy, medicine and so on, the structure of the extraction tank has been continuously improved. After the simple box type mixing clarifier, the EC-D type extraction tank has appeared. The double mixing chamber extraction tank and the double mixing clarifier extraction tank have higher mixing efficiency and clarification efficiency. However, most of the researches on the structure of the extraction tank are focused on the optimization of the mixing chamber and the clarification chamber, and the research on the front chamber is very little. The front chamber is a cuboid cavity located directly below the mixing chamber, which can buffer the materials entering the mixing chamber, increase the contact time between the heavy phase and the light phase, and improve the mixing efficiency. In this paper, the effects of different front chamber structures on suction force, mixing rate and mixing efficiency of impeller were simulated by FLUENT software. The work is as follows: taking the mixing chamber of extraction tank under four kinds of front chamber structure as the research object, the mixing process of feed liquid and P507 in and out of the mixing chamber is simulated, and the suction force of the impeller is obtained. The mixing rate and unit volume mixing energy are used as evaluation indexes to solve the velocity field, pressure field and concentration field in the mixing chamber of four front chamber structures, and to analyze the influence of the front chamber structure on the mixing process. The mixing effect of the compartmentalized mixing chamber is the worst, the suction force of the impeller is the least, the speed of the material being pulled into the mixing chamber is the smallest, the mixing rate of the tubular mixing chamber is the largest, the mixing energy per unit volume is the smallest, the suction force of the impeller is the largest, and the mixing effect is the best. The mixing effect of the non-diaphragm mixing chamber was the second. Considering the mixing effect and the innovation cost of the extraction tank, the enterprise changed the partition type extraction tank into the non-partition type extraction tank, and obtained better test results. However, it is found in the test that the impeller insertion depth is too low, so that the material in front room rotates with the impeller, which is not conducive to the suction of the material, and the water will appear in the organic phase pipeline when the inlet pressure of the heavy phase is high. The material flow in the two-stage extraction tank connected by 90 掳bends is very small. In this paper, the optimum insertion depth of impeller is determined by numerical simulation and experiment, and the connection type of two-stage pipe is changed to elliptical tube. The tubular extraction tank is still the best structure for the front chamber of the extraction tank because of the reason of the cost of the enterprise transformation at present. This paper further optimizes the structure size of the chamber. With the suction force and stirring power as the evaluation index, the velocity field of the mixing of two phase materials is solved, and the optimum insertion depth, suction aperture value and stirring speed of the impeller are obtained, which results in the maximum suction force at the same time when the power loss of the impeller is low.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.83

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