电场-旋流耦合强化多相介质分离研究进展

概述了国内外基于电场-旋流耦合场来强化非均多相分离的研究进展,并对相应强化分离方法进行分析与归纳。根据不同介质类别分别介绍了电场-旋流耦合强化液-液分离、气-固分离、气-液分离、固-液分离等多相介质分离技术、设备及工作原理,例如：动态/静态静电旋流脱水装置、静电旋风除尘器/摩擦旋风分离器、静电旋风除雾器及电动旋液分离器。总结了电场类型与分布、耦合场与液滴、颗粒作用、耦合场数值模拟方法等,为研究电场-旋流耦合强化分离多相介质提供依据。针对特殊多相介质（如黏度大、密度差小及弱/无电导率等）分离性能较差的问题,本文提出应综合考虑耦合设备的结构尺寸、操作参数及安装条件,在提高分离效率的基础上,应加强电场-旋流耦合装置运行安全性的研究以扩大耦合强化多相介质分离的适用范围。     

新型旋流场-颗粒床耦合分离设备静压分布

新型旋流场-颗粒床耦合分离设备将旋风分离器离心分离和移动床吸附/过滤分离有机结合,在一套设备中实现了两级净化过程,可适应较高的温度范围,为气体净化技术提供了一种新的思路。在固定床操作模式下,测量了耦合设备内部轴向、周向和径向的静压分布。实验结果表明,设备入口环形空间的静压分布可以确定设备内部旋流强度与入口气速之间存在直接联系;设备内部负压中心以及旋流场产生的影响在N8（H=2175 mm）测点以下不再明显;设备静压分布在周向上呈现明显的非对称分布,这也反映出设备内的气相流动在周向上存在不均匀分布的现象。     

基于入口分散相重排序的旋流强化分离研究进展

随着工业化进程的飞速前进，适用于分离多相不互溶介质的旋流分离器已广泛应用于石化、环保等重点行业。为了提高旋流分离器在全粒径范围内分散相的分离效率，涌现出了多种旋流分离过程强化技术。其中，对入口分散相进行重排序的旋流强化技术因具有加工成本及运行费用低、易于实施、强化效果明显等优势，展现出了重要的应用价值及推广前景。本文聚焦于入口分散相重排序的旋流强化技术，对基于惯性力场和离心力场进行分散相重排序的旋流强化原理、排序器结构类型及应用于液-液、固-液、气-固两相的分散相重排序强化技术及研究成果进行了系统的分析和总结。在此基础上，从组织构建分散相重排序后的多股液流，选择促进多股液流间协同高效分离的旋流场入射方案，强化分散相移动过程中的聚并长大和/或惯性碰撞等角度出发，总结了分散相重排序的技术路线并进行研究展望，从而指导旋流器的旋流分离过程强化及优化设计，助力于旋流分离效率的深度提升。     

微尺度过程强化的结晶颗粒制备研究进展

结晶颗粒制备技术在化工、医药、电子、生物等领域具有不可替代的作用。近年来,随着化工过程强化和微化工技术的快速发展,基于微尺度的过程强化方法在晶体颗粒制备过程中得到广泛的应用,成为高端颗粒制备的前沿技术。本文系统综述了该领域的研究进展：围绕微流控组件,简述微结构混合器、微流体技术对提高微观混合效率的原理及其在纳米材料、药物结晶等领域的应用;围绕微尺度力场,综述超重力旋转填充床的结构设计、可视化研究,超声场为代表的声空化效应及外加力场对超细纳米颗粒制备和药物连续结晶过程的应用;进一步,针对新型膜微尺度传质强化过程,分析微孔膜材料强化传质过程以及膜表面的晶体颗粒“黏附-生长-脱落”运动行为,阐明影响微孔膜分散传质强化过程的关键结构和过程参数,系统论述致密膜液层强化传质的表面更新机制和控制结晶颗粒制备的多级膜操作系统。最后,展望微尺度过程传质强化的结晶颗粒制备技术发展趋势。     

液-固微旋流分离技术脱除水中催化剂颗粒

回顾了某化工装置中急冷水夹带催化剂颗粒的危害及现阶段国内对含微细固体颗粒废水的分离方法,通过对急冷水特点的分析以及各种分离方法的比较,提出采用一级澄清二级浓缩的两级微旋流分离技术脱除急冷水中的催化剂的方法;阐述了微旋流分离器的工作原理及设备结构;介绍了整个分离系统的运行情况。根据装置的操作特点,通过对操作方法的优化,使分离效率达到72%,有效地脱除了急冷水中的催化剂,成功实现了液-固微旋流分离技术在工业化煤化工装置中的应用。     

含硫污水汽提装置中除油措施及应用

对近年来国内典型的除油措施及应用进行了综述.重点介绍了重力沉降技术,根据油、水两相间的密度差或结合破乳剂、增设过滤器、增设分布器及油水分离器,在重力作用下进行分离,尤其对浮油处理效果显著;旋流分离技术,基于离心分离的原理,适用于污染源油的控制;罐中罐技术,运用水力旋液离心分离的方法进行油、水、固三相分离,具有较高的除油能力和缓冲能力.     

液液萃取塔研究的若干新进展及展望

液液萃取是应用广泛的分离技术,在石油化工、制药提取、金属分离等领域都有重要的应用。萃取塔作为常见的分离设备当前的设计还十分依赖于以往的经验,需要进行大量的实验。文章综述了萃取塔设备的研究现状,总结了对塔内流场、液滴和浓度场的实验测量技术,介绍了基于液滴的模型化方法和多尺度计算流体力学模拟方法,归纳了过程强化的相关研究进展。并对萃取塔未来的研究发展进行了展望,在数字化和可持续的发展背景下,未来在实验方面可以关注实时测量和优化,模型化方面关注于微观界面行为和传质影响的描述,在基于先进的实验和模拟技术基础之上,结合新萃取体系进行萃取设备和内构件的开发,从而实现过程强化,以解决化工过程面临的共同挑战。     

高效旋流过滤分离器

一、产品和技术简介： 旋流过滤分离器是将离心分离、过滤分离等技术有机结合而开发出的全新高效分离设备。该分离器采用上下两个旋流分离腔室和多组螺旋道筒体等结构形式，与传统离心分离设备比较，体积缩小，是常规重力分离器的1／3，但效率远高于常规重力分离器。需净化的气体在旋转直径很小，较小气体流量和较低的气速工况下仍有较强的离心力场。该分离器对液体颗粒与固体颗粒均有较高的分离效率：     

旋流场中小颗粒污染物凝并及运动特性研究

为研究旋流对小颗粒凝并过程的影响,研究通过整合Lech Gmachowski Brown凝并核模型、湍流凝并核模型和XIAO提出的剪切破碎核模型,建立了一个考虑剪切流影响的适用于全粒径范围的颗粒凝并模型。首先计算了初始粒径为0.5μm的颗粒凝并效率,对比前人实验数据,验证了新模型对于湍流场过渡区内颗粒凝并行为的适应性。然后考察了旋流运动对亚微米和微米级颗粒凝并的影响,结果表明,旋流影响了亚微米级颗粒的自由扩散,促使不同粒径颗粒分离,从而降低凝并效率;对于微米级颗粒,旋流增加了小颗粒的碰撞概率,但无法提升凝并效果,旋流速度越高,凝并效果越差;在旋流场中设置轴向扰流板,可以改善小颗粒凝并效果。     

风城特稠油沉降罐污水旋流除油试验研究

我国大部分油田随着原油含水量的逐年上升,油水分离能力均因扩容困难而不能满足生产需要。旋流除油装置是在离心力的作用下根据两相间的密度差来实现分离的,由于离心力场的强度比重力场大得多,因此旋流除油装置比重力分离设备的效率大得多,同时具有结构简单、体积小、重量轻、处理时间短等特点。依据相关试验对旋流除油装置的反相破乳剂加药浓度、溢流比、处理量等参数进行了优选,最终结合现场生产情况对整个试验作出评价,分析存在的问题并提出了相应建议。     

Study of Air‐Liquid Flow Patterns in Hydrocyclone Enhanced by Air Bubbles

In order to improve the oil‐water separation efficiency of a hydrocyclone, a new process utilizing air bubbles has been developed to enhance separation performance. Using the two‐component phase Doppler particle analyzer (PDPA) technique, the velocities of two phases, air and liquid, and air bubble diameter were measured in a hydrocyclone. The air‐liquid mixing pump can produce 15 to 60 μm‐diameter air bubbles in water. There is an optimum air‐liquid ratio for oil‐water separation of a hydrocyclone enhanced by air bubbles. An air core occurs in the hydrocyclone when the air‐liquid ratio is more than 1 %. The velocities of air bubbles have a similar flow pattern to the water phase. The axial and tangential velocity differences of the air bubbles at different air‐liquid ratio are greater near the wall and near the core of the hydrocyclone. The measured results show that the size distribution of the air bubbles produced by the air‐liquid mixing pump is beneficial to the process where air bubbles capture oil droplets in the hydrocyclone. These studies are helpful to understand the separation mechanism of a hydrocyclone enhanced by air bubbles.     

Performance characteristics for particles of sand FCC and fly ash in a novel hydrocyclone

With growing industrialization in power sector and petrochemical industries water has been contaminated with particulates like sand, fly ash and FCC. In the present investigation, a new type of hydrocyclone was designed and fabricated. The system is designed in such a manner that it can operate in a wide range of variables for sand, sand-ash and sand-FCC systems. A detailed study on performance analysis of hydrocyclone, pressure drop, cut size particle diameter and particle characterization has been carried out for the design of the hydrocyclone. A mathematical model for predicting particle separation efficiency and cut size particle diameter has been developed. A correlation has been developed for percentage removal of particles and retention of particles in the hydrocyclone. An experimental finding shows 96% removal efficiency for particle with cut size diameter of , which can meet the required separation in industrial application.     

Improvement of performance efficiency of a hydrocyclone with design modification by suppressing air core

Hydrocyclones have been used for beneficiation of coal and mineral in coal washeries and mineral process industries. To enhance the efficiency of hydrocyclone, it is very essential to quantify the presence or absence of air core within the hydrocyclone. In the present study, for the first time, a new hydrocyclone design has been conceptualized and tested for its efficiency in separation of particles based on gravity. Experimental investigations have been carried out using design of experiments and the results have been analyzed statistically. The results have shown that suppressing the air core improves the separation efficiency of the hydrocyclone. Efforts have been made to explain the concept through fundamentals of fluid flow in hydrocyclone. The air core has a significant effect on particle separation as the relative density of the particles approach to the fluid density. The results will be used in the development of a new design of dense medium hydrocyclone at industrial scale that will improve the separation efficiency of the hydrocyclones by separating the near gravity particles more efficiently.     

脱气除油旋流系统流场分布及分离特性

目前我国大部分油田已进入高含水阶段，且采出液中常带有大量伴生气，采用旋流分离法实现采出液高效分离对于简化陆上油田地面处理工艺及提升海上平台经济环保的采出液处理技术具有重要意义。脱气除油旋流系统由GLCC型气液分离器和油滴重构旋流器串联组成，设计的目的是在保证高效脱气的同时进一步改善对小油滴的去除效果，实现油气水三相高效分离。本文基于计算流体动力学（computational fluid dynamics，CFD）方法，利用种群平衡模型（population balance model，PBM）模拟油滴破碎与聚结，对脱气除油旋流系统内部流场特性及粒度分布进行模拟分析，并采用数值模拟与试验相结合的研究方法，对比分析不同含气体积分数和气相出口分流比对脱气除油旋流系统分离性能的影响规律。结果表明：含气体积分数与气相出口分流比对脱气除油旋流系统分离效率的交互作用较显著，在研究范围内综合脱气效率和除油效率可以得到，含气10%、20%、30%的最佳分流比分别为25%、30%、35%，数值模拟结果与试验结果吻合良好，验证了数值模拟方法的可靠性。另外，含气体积分数越大，油滴重构旋流器的油滴分层重构现象越明显，油滴重构旋流器可以在一定程度上改善含气情况下油水分离效果差的现象，脱气除油旋流系统对油气水三相分离的适用性较好。     

液-液水力旋流器分离效率深度提升技术探讨

为解决微小粒径分散相分离效率不高,制约水力旋流器分离效率深度提升的问题,本文以液-液水力旋流器为分析对象,在总结已有理论及研究成果基础上,分别从影响旋流分离效率的关键物理因素,包括分散相在旋流场内的停留时间、分散相粒径、分散相距轴心旋转半径、分散相切向旋转速度以及旋流分离工艺系统五个方面出发,首先对已有提升旋流分离效率的水力旋流器串联工艺、分散相粒径聚结器、小直径旋流分离器及增强切向速度的动态水力旋流器等技术措施进行分析总结,并在此基础上提出了促进旋流分离效率深度提升的新型技术方案,为液-液两相以及固-液、气-液、气-液-固等多相混合介质的高效旋流分离器设计及系统优化提供一定理论及技术支撑。     

A Comparative Study on the Separation of Different‐Shape Particles Using a Mini‐Hydrocyclone

The separation efficiency from water of different‐shape particles was studied experimentally using a mini‐hydrocyclone. Spherical and flaky (plate‐like) aluminum particles with the same particle size distributions were employed. Also, the effects of the feed flow rate and the temperature on the separation performance were studied. The results were investigated in terms of slurry recovery, total efficiency, and partition curves. The separation efficiency of the spherical particles increased with increasing particle size, temperature, and feed flow rate, as expected. The fishhook effect, as a noticeable phenomenon, was observed for the spherical particles. In case of the flaky particles, the separation showed an unusual behavior: The separation efficiency decreased with increasing particle size in the largest particle fraction, which has so far not been reported and addressed in this way.     

Process intensification of synthesis of magnetite using spinning disc reactor

An instantaneous co‐precipitation reaction for the synthesis of magnetite particles has been investigated in conventional mechanically agitated reactor and novel spinning disc reactor (SDR) with an objective of process intensification. Characteristics of the particles have been analysed using Coulter Counter particle analyser. It has been observed that the particle size distribution is more uniform with overall lower power consumption in the SDR as compared to the conventional reactors. With a viewpoint of improving the synthesis process in terms of the obtained conversion levels in the SDR, effect of different operating parameters viz. rotational speed, diameter and type of the disc, flow rate of the reactants and the operating temperature on the synthesis process has also been investigated. It has been observed that the flow rate of the reactants as well as disc characteristics have a significant influence on the extent of conversion. Overall, it has been established that the SDR gives excellent particle size distribution characteristics as compared to the conventional approaches and hence results in process improvement/intensification for magnetite synthesis process at comparatively lower energy inputs.     

DEM simulations of spherical particle–particle collisions

The randomness, diversity, and complexity of the high-speed particle crushing process bring great difficulties to the theoretical analysis of powder engineering. In this paper, the discrete element method is used to simulate the collision of spherical particles, which provides a reference for studying the process and mechanism of crushing between particles under impact load. The Hertz–Mindlin with bonded contact model is used as the particle–particle contact model. The central collisions of particles with different diameter ratios under different high-speed motions and the eccentric collisions with different eccentricities are discussed. The results show that the bond damage increases with the increase of relative velocity in both centre impact and eccentric impact. In centre collisions, particles of smaller objects are more fragmented than particles of larger objects. For smaller target particles, the larger the diameter ratio is, the more particle elements are detached from the target particles, and the greater the bond breakage rate. For larger target particles, the larger the diameter ratio is, the less the particle element falls off and the smaller the bond breakage rate. This provides guidance for the collision and crushing of particles with different particle size ratios and different eccentricities during high-speed motion in engineering applications in the future.     

CFD Study on the Effect of Hydrocyclone Structure on the Separation Efficiency of Fine Particles

Abstract

Effects of geometric structure parameters of 10 mm-diameter hydrocyclones on the particle separation efficiency are studied using computational fluid dynamics (CFD). The fluid velocity profiles and particle trajectories are simulated using RFLOW software with a standard isotropic k-ε turbulent model. The JIS standard CaCO₃-17 particles are adopted as a particulate sample in simulations and experiments. Comparing the simulated results with experimental data, a maximum deviation about 20% in partition curves occurs for 5–10 µm particles. However, fairly good agreements for the cut-size predictions and the fish-hook phenomenon are obtained. The simulated cut-size d ₅₀ is only 2 µm larger than that measured in experiments, while the value of d ₁₀₀ can be accurately predicted. An increase in overflow diameter or a decrease in underflow diameter leads to a lower separation efficiency but a clearer separation sharpness due to lower fluid underflow rate. A short-and-wide rectangular inlet is more efficient for particle separation than a tall-and-narrow one. An inclined inlet conduit plays an inessential role on the efficiency improvement but gains a 2 µm reduction in d ₁₀₀. Comparing the simulated results, the hydrocyclone used in the experiments of this study exhibits a higher separation sharpness than the Rietema type and a higher efficiency than the Bradley type based on the same operation capacity and hydrocyclone size.