双级串联旋流器电石渣纯化技术及CFD数值模拟

发布时间：2018-05-12 04:25

本文选题：电石渣 + 双级串联　；参考：《石河子大学》2017年硕士论文

【摘要】：电石渣是工业水解电石制备C2H2、C2H4O、PVC等化学物质后产生的一种碱性废弃物,其主要成分为氢氧化钙Ca(OH)2,pH值约为14,具有强碱性。当前我国经济高速发展,C2H2、C2H4O、PVC等化学物质的需求量越来越大,产生大量的电石渣导致周边环境遭到严重破坏。目前,公认的电石渣最好的处理方法就是将其进行煅烧成石灰作为生产电石的原材料,但该方法要求电石渣中有较高含量的Ca(OH)2,为了实现电石渣煅烧后再加工成电石循环利用,电石渣的纯化技术至关重要。本文针对电石渣中Ca(OH)2的纯化,设计了双级串联水力旋流器,通过试验研究和流场分析,验证了电石渣中Ca(OH)2纯化的有效性,主要研究内容如下:(1)采用XRD(X射线衍)和化学滴定方法研究电石渣的理化性质,测得电石渣组成成分、粒径分布区间以及Ca(OH)2分布规律,分析发现电石渣中Ca(OH)2含量随着电石渣颗粒粒径的减小而增加,综合考虑采用双级串联旋流器对电石渣中Ca(OH)2进行纯化,纯化的目标粒径为75μm。(2)根据电石渣中Ca(OH)2的分布规律,结合水力旋流器分离理论,优选最大切线速度轨迹面分离粒度模型,在现有水力旋流器的基础上建立结构参数之间的约束条件,计算出双级水力旋流器的结构参数,一级水力旋流器:直径50 mm、进料口直径25 mm、溢流管直径15 mm、底流口直径8 mm、柱段高度85mm、溢流管插入深度48mm、锥角6°;二级水力旋流器:直径40 mm、进料口直径14 mm、溢流管直径12 mm、底流口直径8 mm、柱段高度42 mm、溢流管插入深度38 mm、锥角6°。(3)搭建试验平台,依照实际试验情况,使用响应曲面法设计两因素混合水平的中心复合试验方案。对试验结果进行统计学分析,确定电石渣纯化的最佳工艺参数:进料浓度A=16%,进料速度B=1.0 m/s,此时对应的响应指标分别为:溢流分离极限d95=45.33μm,分离效率E=93%,分离精度H=0.45,分股比S=0.42,电石渣处理量Q=356.4 Kg/h。(4)采用Fluent软件对电石渣纯化用双级串联水力旋流器的工作过程进行数值模拟,以进料浓度A=16%,进料速度B=1.0 m/s为基础设定边界条件,从压力场、切向速度场、速度矢量进行数值模拟,分析流场特性对旋流器分离性能的影响。数值模拟结果表明,双级串联旋流器的压力场和切向速度场基本符合常规水力旋流器流场的变化规律,速度矢量图显示流场中出现了严重的短路流,将溢流管改变为锥形溢流管,短路流现象有所改善。
[Abstract]:Calcium carbide slag is a kind of alkaline waste produced after the preparation of C _ 2H _ 2H _ 4O _ 4 PVC by industrial hydrolysis of calcium carbide, the main component of which is calcium hydroxide CaOH _ (2) O _ (2) H _ (2) H _ (2) pH value is about 14, and it has strong alkalinity. At present, the demand for chemical substances such as C _ 2H _ 2C _ 2H _ 4O _ 4 PVC is increasing with the rapid economic development of our country, and a large amount of calcium carbide slag is produced, which results in serious damage to the surrounding environment. At present, the best treatment method of calcium carbide slag is to calcinate it into lime as raw material to produce calcium carbide. However, this method requires a high content of CaOH2 in calcium carbide slag. In order to realize the recycling of calcium carbide slag after calcination and processing into calcium carbide, The purification technology of calcium carbide slag is very important. In this paper, a two-stage series hydrocyclone is designed for the purification of Ca(OH)2 from calcium carbide slag. Through experimental study and flow field analysis, the validity of Ca(OH)2 purification from calcium carbide slag is verified. The main research contents are as follows: (1) the physicochemical properties of calcium carbide slag were studied by XRD(X ray diffraction) and chemical titration method. The composition, particle size distribution interval and Ca(OH)2 distribution law of calcium carbide slag were measured. It is found that the content of Ca(OH)2 in calcium carbide slag increases with the decrease of particle size of calcium carbide slag. Considering the purification of Ca(OH)2 in calcium carbide slag by two-stage series cyclone, the target particle size is 75 渭 m 路m-2) according to the distribution rule of Ca(OH)2 in calcium carbide slag, the content of Ca(OH)2 in calcium carbide slag increases with the decrease of particle size of calcium carbide slag. Based on the separation theory of hydrocyclone, the separation particle size model of maximum tangent velocity locus is selected, and the constraint conditions between structural parameters are established on the basis of the existing hydrocyclone, and the structural parameters of two-stage hydrocyclone are calculated. First-stage hydrocyclones: diameter 50 mm, inlet diameter 25 mm, overflow pipe diameter 15 mm, bottom outlet diameter 8 mm, column height 85 mm, overflow pipe insertion depth 48 mm, cone angle 6 掳; second stage hydrocyclone: diameter 40 mm, inlet diameter 14 mm, overflow diameter 14 mm. The test platform was built with 12 mm diameter of pipe, 8 mm diameter of bottom flow port, 42 mm height of column, 38 mm depth of insertion of overflow pipe and 6 掳. According to the actual test situation, the method of response surface is used to design the central composite test scheme with two factors mixing level. Statistical analysis of the results of the experiment, The optimum process parameters for the purification of calcium carbide slag are determined as follows: feed concentration An 16, feed speed B = 1.0 m / s. The corresponding response indexes are as follows: overflow separation limit d95m 45.33 渭 m, separation efficiency EQ 93cm, separation accuracy H 0. 45, splitting ratio S 0 42, calcium carbide slag treatment quantity Q 356.4 kg / h 路4). The working process of two-stage series hydrocyclone for calcium carbide slag purification was simulated by Fluent software. On the basis of feed concentration A16 and feed velocity B1. 0 m / s, the boundary conditions are set up. Numerical simulation is carried out from pressure field, tangential velocity field and velocity vector to analyze the effect of flow field characteristics on the separation performance of hydrocyclone. The numerical simulation results show that the pressure field and tangential velocity field of two-stage series hydrocyclone basically accord with the variation law of conventional hydrocyclone flow field, and the velocity vector diagram shows that there is a serious short-circuit flow in the flow field. When the overflow tube is changed into a cone overflow tube, the short-circuit flow phenomenon is improved.
【学位授予单位】：石河子大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X78

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