海水提钾关键设备的优化研究

发布时间：2018-06-24 03:50

本文选题：计算流体力学 + Fluent模拟　；参考：《河北工业大学》2015年硕士论文

【摘要】：在农业生产中钾肥是一种必不可少的肥料,但是陆地中的钾储量很低,且不易开采,而海水中钾的储藏量十分可观,因此对已工业化的斜发沸石离子交换法提钾技术的研究具有十分重要的意义。硫酸钾是一种十分优质的无氯钾肥,通过对结晶器内流场的模拟优化实验条件,确保硫酸钾晶体粒度足够大。因此本文对离子交换柱内流场和硫酸钾结晶器内流场分布进行了模拟研究。本文利用Fluent软件对离子交换柱内流场进行计算,并通过改变离子交换柱直径、入口流速、入口管道直径、填料高度和进口数对所得流场速度分布、速度矢量分布、速度范围分布以及压力分布进行分析,得到不同条件对交换柱内流场的影响,并且确定了最适宜工艺条件:离子交换柱直径为3 m,入口流速为0.10 m/s,入口管道直径为0.8 m,填料高度为8 m,并分析结果可知交换柱选取两进口两出口利于离子交换过程。完成离子交换柱内流场模拟后对结晶器流场进行模拟。首先,通过实验结果与模拟结果对比完成了模型验证,证实了结晶器流场模拟的合理性。之后改变结晶器结构、导流筒结构、桨叶转速、桨叶直径、桨叶位置、固体粒径进行模拟计算,并分析上述条件对结晶器内流场分布、湍流动能分布、晶体混匀时间、晶体不均匀度以及搅拌轴功率的影响。结晶器模拟结果表明:结晶器内挡板的安装改变了流体流型,减少了混合时间,增加了搅拌效率,利于结晶相的均匀分布。在导流筒直径为100 cm,高度为110 cm的时候流体流型规范,混合时间短,混合效率高,不均匀度低,搅拌轴功率也不大。搅拌桨转速和直径的变化对流体流型以及流线没有影响,最终搅拌桨最佳转速选取150 rpm、最佳直径为90 cm。搅拌桨安装最适位置为H/3,而结晶器不均匀度会随着固体粒径的增大而变大。
[Abstract]:Potash is an essential fertilizer in agricultural production, but the potassium reserves on land are low and difficult to exploit, and the amount of potassium stored in seawater is considerable. Therefore, it is of great significance to study the technology of ion exchange extraction of potassium from clinoptilolite. Potassium sulfate is a kind of high quality chlorine free potassium fertilizer. By simulating the flow field in the mold, the experimental conditions are optimized to ensure that the crystal size of potassium sulfate is large enough. In this paper, the flow field in ion exchange column and in potassium sulfate crystallizer are simulated. In this paper, the flow field in the ion exchange column is calculated by fluent software, and the velocity distribution and velocity vector distribution of the flow field are analyzed by changing the diameter of the ion exchange column, the inlet velocity, the inlet pipe diameter, the packing height and the inlet number. The velocity range distribution and pressure distribution are analyzed, and the influence of different conditions on the flow field in the exchange column is obtained. The optimum technological conditions are determined as follows: the diameter of ion exchange column is 3 m, the inlet flow rate is 0.10 m / s, the diameter of inlet pipe is 0.8 m, and the height of packing is 8 m. The results show that the selection of two inlet and two outlet of exchange column is beneficial to the process of ion exchange. After the simulation of the flow field in the ion exchange column, the flow field of the crystallizer is simulated. First, the model verification is completed by comparing the experimental results with the simulation results, and the rationality of the flow field simulation of the crystallizer is verified. Then the mold structure, flow tube structure, blade speed, blade diameter, blade position and solid particle size are simulated and calculated. The distribution of flow field, turbulent kinetic energy and crystal mixing time are analyzed. The effect of crystal unevenness and stirring shaft power. The simulation results show that the installation of the baffle in the mold changes the fluid flow pattern, reduces the mixing time, increases the stirring efficiency and facilitates the uniform distribution of the crystalline phase. When the diameter of the tube is 100 cm and the height is 110 cm, the mixing time is short, the mixing efficiency is high, the inhomogeneity is low, and the mixing axis power is small. The change of speed and diameter of the impeller has no effect on the flow pattern and streamline. The optimum speed of the impeller is 150rpm and the optimum diameter is 90cm. The optimum position of impeller installation is H / 3, and the inhomogeneity of the crystallizer increases with the increase of solid particle size.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ440.53

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