压滤CFD模型及脱水过程的优化研究

发布时间：2018-06-24 11:48

本文选题：过滤脱水 + 压滤机　；参考：《江西理工大学》2015年硕士论文

【摘要】：选矿精矿的过滤脱水是选矿厂的一个十分重要的环节。以往,选矿厂主要采用真空过滤方法进行矿物的过滤。但随着复杂难选和低品位矿物越来越多,选矿精矿变得越来越细而黏,真空过滤机由于受到大气压的限制往往难以处理细而黏的物料。而压滤机由于可以提供数倍于大气压的过滤推动力,能够很好地胜任细而黏物料的过滤,所以,近年来压滤机被越来越广泛地应用在选矿精矿中的过滤。压滤机的脱水过程一般包括“进浆成饼、压榨和风干”三个过程。滤板进料方式的不同直接影响到进浆成饼过程的效率和对滤板的磨损程度等,而压滤机的进料方式一般有上部进料、下部进料和中部进料三种。本文利用计算流体力学(CFD)原理,通过建立不同进料方式的压滤CFD建模,对三种进料方式进行了仿真研究,发现上部进料方式更利于形成均匀滤饼,滤布更不容易磨损,且滤板受压更为均匀,成饼速率最高。在此基础上,本文还利用建立的上部进料方式(单面过滤)的CFD模型对压滤的成饼过程进行了仿真研究,研究得出每种矿物的压滤脱水存在一个最佳的滤饼厚度,当压滤机的滤饼厚度控制在此滤饼厚度时,压滤机的单位时间处理量可以达到最大,作业效率最高,压滤机脱水工作运行在最优状态。除此外,本文还对“压榨、风干及进浆工艺”等三个因素对脱水效率的影响进行了进一步的研究,提出进浆过滤成饼时,提供的进浆压力应从低压逐渐升至高压,同时存在一个合理的压榨时间和风干时间。在以上研究的基础上,通过利用北京矿冶研究总院与云南省云天化集团海口磷矿在该矿选矿厂建立的工业压滤试验系统,进行了试验验证研究,通过采集工业试验数据并对数据进行了分析,分析结果验证了最佳滤饼厚度的存在,并获得了该系统的最佳滤饼厚度的数值。此外还对压榨时间和风干时间的合理数值进行了试验研究。在以上研究的基础上,本文还提出了使压滤机工作在最佳滤饼厚度的几种工业控制实现方案。如:压力控制法、时间控制法、流量控制法等。并对不同进料方式、压榨时间、风干时间和进浆工艺的优化结果在工业压滤中的应用,提出了一些建议和优化方案。总之,本文通过研究建立压滤成饼的CFD模型,对压滤脱水过程进行了模拟仿真,提出了压滤机脱水过程的优化方向,并通过工业试验研究对CFD建模仿真研究的结论进行了试验验证,并提出了几种工业可实施的优化控制方案。对工业压滤机的设计及脱水过程的优化具有一定的积极意义。
[Abstract]:Filtration and dehydration of concentrate is a very important link in concentrator. In the past, mineral processing plants mainly used vacuum filtration method to filter minerals. However, with the increasing number of complex refractory and low-grade minerals, the concentrate becomes more and more fine and sticky, and the vacuum filter is often difficult to deal with fine and sticky materials because of the atmospheric pressure constraints. Because the filter press can provide several times the pressure of the filter driving force, it can be used for the filtration of fine and sticky materials, so in recent years, the filter press has been more and more widely used in the filtration of concentrate. The dehydration process of filter press generally includes three processes: cake, press and air drying. The different feed ways of filter plate have direct influence on the efficiency and wear degree of the cake making process, while the feed mode of filter press generally includes three kinds of feed: upper feed, lower feed and middle feed. Based on the principle of computational fluid dynamics (CFD) and the modeling of pressure filter CFD with different feeding methods, three feeding methods are simulated in this paper. It is found that the upper feeding method is more conducive to the formation of uniform filter cake, and the filter cloth is less easy to wear. The filter plate is more evenly pressed and the rate of cake formation is the highest. On this basis, the cake forming process of pressure filtration is simulated by using the CFD model of the upper feed (single side filtration). The results show that there is an optimum filter cake thickness for each mineral. When the filter cake thickness of filter press is controlled at the filter cake thickness, the processing capacity per unit time of filter press can reach the maximum, the working efficiency is the highest, and the dehydration operation of filter press is in the optimal state. In addition, the effects of three factors, namely press, air drying and pulp feeding, on the dehydration efficiency are further studied. It is suggested that the feed pressure should be increased gradually from low pressure to high pressure when the pulp is filtered into cake. At the same time, there is a reasonable press time and air drying time. On the basis of the above research, the industrial pressure filtration test system established by Beijing General Research Institute of Mining and Metallurgical Research and Yunnan Yuntianhua Group Haikou Phosphate Mine in the concentrator of this mine has been tested and verified. By collecting and analyzing the industrial test data, the results verify the existence of the optimum filter cake thickness, and obtain the value of the optimal filter cake thickness of the system. In addition, the reasonable values of press time and air drying time were studied experimentally. On the basis of the above research, this paper also puts forward several industrial control schemes to make the filter press work in the optimum filter cake thickness. For example: the pressure control method, the time control method, the flow control method and so on. Some suggestions and optimization schemes are put forward for the application of the optimization results of different feed ways, press time, air drying time and pulping process in industrial pressure filtration. In a word, the CFD model of pressure filter cake is established, the process of pressure filter dehydration is simulated, and the optimization direction of pressure filter process is put forward. The conclusion of CFD modeling and simulation is verified by industrial experiment and several industrial optimal control schemes are put forward. It has certain positive significance for the design of industrial filter press and the optimization of dehydration process.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD462.2

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