水滴间距对高压高频脉冲静电聚结特性的影响

为了深入探究W/O乳状液静电聚结过程中水滴间距对静电聚结特性的影响,本文在高压高频脉冲电场条件下,通过实验研究了水滴间距对水滴平均变形度及相互靠近速率的影响.结果表明:随着电场施加时间增加,水滴相互靠近,水滴的平均变形度随聚并时刻比的增大而增大;不同粒度条件下,随着水滴中心距比的增大,水滴的平均变形度呈现下降的趋势,水...     

高效聚结器在氯乙烯生产中的应用

介绍了氯乙烯深度脱水工艺及聚结器脱水原理,将高效聚结器应用于氯乙烯精馏工序中,实现了氯乙烯的深度脱水,满足了聚合工序的工艺要求,提高了产品的质量。     

液滴聚结过程中随机因素的分析

推导了扩散相液滴运动轨迹模型和基本流模型,并优化了计算方法,同时,将分层二相流中的界面波用于聚结机理的研究。直接数值模拟结果表明:波数对液滴在界面处的平均速度、相对速度及绝对速度的影响不明显,但对液滴所受到的不平衡剪力有显著的影响;波数的变化将使液滴的旋转运动具有倾向性,较大的波数比较小的波数对液滴的运动方式影响显著;界面波的存在使得液滴的运动方式更具有复杂性,尽管流动状态为层流,界面波的存在也会使液滴所受到的不平衡剪力与液滴直径的关系曲线发生变化,其中既包含有随机因素也包含有确定性因素;波数对阿基米德数与雷诺数的关系曲线的影响也具有一定的随机因素,但这些曲线的偏移量变化不大,这将为理论计算和工程上的简化应用提供一个良好的平台。     

聚结器浓度场的数值模拟

为优化聚结器结构,应用计算流体力学（CFD）方法,选用RNG k-ε模型,以SIMPLE算法为基础,对旋流式和蛇形管式聚结器在湍流状态下的流体流动场进行数值模拟,得出该两种结构聚结器的油相浓度分布云图。数值模拟结果表明,蛇形管式聚结器对油滴的兼并和聚结效果优于旋流式聚结器。     

炼厂污油静电聚结脱水研究

针对目前炼油厂污油乳化严重、高含水、高含盐、性质复杂难处理的特点,在现有的静电聚结理论研究基础之上,采用绝缘复合电极装置,开展静电聚结污油脱水研究。通过静电聚结脱水试验考察了绝缘电极杆长度、电压、停留时间、温度、注水量等因素对污油脱水效率的影响。试验结果表明,对某炼厂含水率为15.36%的污油,进行一级电脱分离,即可满足污油脱后含水率小于0.5%的回炼指标,脱水效率可达97%以上。     

结构形式对聚结器性能影响的数值分析

利用计算流体动力学(Computational Fluid Dynamics,CFD)软件Fluent,采用群体平衡模型(Population Balance Model,PBM),以常规双锥型液-液旋流分离器结构为基础,研究聚结器Ⅰ～Ⅵ(不同结构形式)对聚结性能的影响。分析了不同截面上油相体积分布、油相粒径分布及油相迹线分布等,对不同粒径聚结性能的影响,获取了不同结构形式聚结器出口粒径分布和变化规律。结果表明:油相在聚结器Ⅴ经聚结后出口粒径最大可以达到290μm,且含有粒径270、290μm的油相数量最多。同时在截面3,聚结器Ⅴ粒径最大,且整体看聚结器Ⅴ粒径大多集中在200μm,表明聚结器Ⅴ聚结效果最好。     

高压静电破乳中离散液滴的动力学分析

考虑乳化液离散液滴的直径分布,对高压直流静电破乳过程中离散液滴的运动进行了理论模拟。模拟及实验结果表明,在高压静电作用下,离散滴液从一侧电极向另一侧电极运动。沿液滴运动方向,液滴浓度逐渐增大,并在电极附近达到最大。随着静电作用时间的延长,电极附近液滴浓度近似呈线性规律增大。在相同的作用时间内,高电压液滴浓度的增长幅度要更大。因此,尽可能提高施加电压要比单纯延长静电作用时间的破乳效果更好。此外,大的液滴运动速度更快,故对于离散相滴径较大的乳化液,破乳效率会更高。     

聚结器在氯乙烯单体除水中的应用

介绍了河南联创化工有限公司氯乙烯单体含水的除去方法,一期采用固碱干燥,二期采用高效聚结器,运行后,树脂粉的白度有了显著提高,热稳定性等更加稳定。     

静电强化乳液中油滴(纳米尺度)聚并过程(英文)

Oil droplets in nanometer scale which are dispersed in water cannot be separated easily.An attractive technique is carried out by electrical phenomena to demulsify oil in water emulsion.In this research,non-uniform electric field or dielectrophoresis(DEP) is applied to remove sunflower oil(which is dispersed in the water).Effects of temperature,time and voltage(using AC-electric field) were considered to get the highest DEP-force(Fdi) and the best results.The oil particles sizes with average of approximately 76 nm have been shown using a ZetaSizer Nano ZS,Model ZEN 1600(Malvern Instrument Ltd.).The maximum separation efficiency of 85% is obtained at the optimum temperature of 38 ℃ and voltage of 3000 V.     

Effectiveness and limitations of two drop studies to explain emulsion dehydration under modulated electric fields

Electrocoalescence has long been known for the separation of a water-in-oil emulsion. An associated challenge with electrocoalescers is the undesired noncoalescence and consequently chain formation of aqueous phase droplets. This leads to low separation efficiency and damage of electrical equipment. Recently Hasib et al. proposed an electric field modulated scheme that showed significant improvement in dehydration of water-in-oil emulsions. They investigated the range of modulation parameters when the scheme is most effective. The fundamental process in electrostatic dehydration of an emulsion is the interaction between a pair of water droplets. In the present study, two suspended aqueous drops in insulated oil experiments are compared for their behavior under unmodulated and modulated electric fields. Further, a model is developed and the experimental behavior under unmodulated and modulated electric fields is compared with numerical solutions. The model predicts the experimental observations accurately by balancing electrostatic, electrophoresis, dipolar, and resisting viscous drag forces, ignoring the end (bridge) effect during the contact. The study shows that the increase in the rate of dehydration of a water-in-oil emulsion under modulated electric fields with an increase in duty ratio and its near independence on the modulation time period can be explained by the two-drop studies. However, several other processes such as multidrop interactions as well as scavenging of fine droplets by charged droplets created as intermediates in the interaction of two droplets cannot be explained by the two-drop studies.     

高压/高频脉冲交流电场中W/O型乳化液的静电聚结特性研究

采用矩形流道连续流动实验装置,对W/O型乳化液施加矩形波高压/高频脉冲交流电,以分散相水颗粒体积平均粒径为主要技术指标,研究了电压幅值、脉宽比、脉冲频率等电场参数对不同含水率乳化液静电聚结特性及电源功率的影响.结果表明,电压幅值是影响聚结效果的主要因素,水颗粒粒径随电压的升高而增大;脉宽比对聚结效果和功率的影响较小;脉...     

电场作用下双液滴聚合特性

乳状液破乳分离是目前高含水期油田开采过程中难以解决的技术问题,电场破乳方法具有高效清洁等优点,是解决该问题的有效手段。采用数值模拟与试验验证相结合的方法研究电脱水过程中阶跃、斜坡电场诱导下双液滴的聚合与分离特性。结果表明,在斜坡电场作用下,界面张力引起的泵吸作用大于电场力引起的颈缩作用,有利于液滴聚并,且液滴发生二次乳化现象的概率降低。而施加阶跃电场时,一定范围内能够达到液滴破乳的目的,但液滴在聚并过程中易发生二次乳化现象。从电场对连续相影响的角度分析发现,阶跃电场不仅对液滴具有驱动作用,对连续相的影响也较为明显,阶跃电场会增大连续相内湍流作用,不利于电脱水过程。因此,采用斜坡信号诱导液滴聚合能够降低二次乳化现象发生的概率。     

平板流场内油粒运动碰撞数学模型研究

基于油滴几何轨迹交叉来认可油滴发生碰撞建立了描述液滴间碰撞的数学模型,为油滴间的碰撞提供判断依据,来弥补迄今为止几乎没有可用数据来表示油滴碰撞时间的关系式。其计算结果与采用PDM数值模拟计算结果相吻合,验证所建立的油滴碰撞模型具有一定可靠性。     

Structural Dynamics Support Electrostatic Interactions in the Active Site of Adenylate Kinase

Electrostatic preorganization as well as structural and dynamic heterogeneity are often used to rationalize the remarkable catalytic efficiency of enzymes. However, they are often presented as incompatible because the generation of permanent electrostatic effects implies that the protein structure remains rigid. Here, we use a metric, electric fields, that can treat electrostatic contributions and dynamics effects on equal footing, for a unique perspective on enzymatic catalysis. We find that the residues that contribute the most to electrostatic interactions with the substrate in the active site of Adenylate Kinase (our working example) are also the most flexible residues. Further, entropy-tuning mutations raise flexibility at the picosecond timescale where more conformations can be visited on short time periods, thereby softening the sharp heterogeneity normally visible at the microsecond timescale.     

Coalescence of Water Droplets in Crude Oil Emulsions: Analytical Solution

In petroleum refineries, water is used in desalting units to remove the salt contained in crude oil. Typically, 7 % of the volume of hot crude oil is water, forming a water‐and‐oil emulsion. The emulsion flows between two electrodes and is subjected to an electric field. The electrical forces promote the coalescence of small droplets of water dispersed in crude oil, and these form bigger droplets. This paper calculates the forces acting on the droplets, highlighting particularly the mechanisms proposed for droplet–droplet coalescence under the influence of an applied electric field. Moreover, a model is developed in order to calculate the displacement speed of the droplets and the time between droplet collisions. Thus, it is possible to simulate and optimize the process by changing the operational variables (temperature, electrical field, and water quantity). The main advantage of this study is to show that it is feasible to increase the volume of water recycled in desalting processes, thus reducing the use of freshwater and the generation of liquid effluents in refineries.     

一种快速判断静电喷枪空间电场的方法

分析了静电喷枪产生故障的原因。提出了一种快速判断静电喷枪空间电场的方法。讨论了这种方法的原理和使用中的注意事项。     

高压静电技术在固液相分离中的应用

论述了静电分离技术在固液相分离等中的发展和应用。