Effect of Structural Parameters on Drop Size Distribution in Pulsed Packed Columns

The effect of packing type on drop size distribution in pulsed packed columns was investigated by means of different columns and three packing types with three liquid systems including n‐butyl acetate, toluene, and kerosene with water. These liquid systems cover a wide range of interfacial tensions. Also the influence of operating variables in terms of pulse intensity and volumetric flow rates of dispersed and continuous phases was examined. Pulse intensity, interfacial tension, and packing shape were found as the main important factors for drop size distribution while volumetric flow rates had no significant effect. Correlations are presented to predict drop distribution and mean drop size in pulsed packed columns.     

填充床中空隙率分布的研究综述

综述了充床中空隙率径向分布的几种主要测量技术和数学模型,概括了空隙率分布的一般规律,为试验研究和工程设计工作提供重要依据。     

Holdup and Pressure Drop of Packed Beds Containing a Modular Catalytic Structured Packing

A comparative experimental study has been carried out to establish the hydraulic behavior of a new modular catalytic packing (Sulzer's Katapak^®‐SP 12) and the hybrid packed bed consisting of a catalytic packing section placed in between two sections comprising elements of a high capacity structured packing (MellapakPlus 752.Y). Air‐water experiments were carried out at ambient conditions using a Perspex column with an internal diameter of 0.45 m. As expected, the liquid holdup and the pressure drop of the combined bed were between those measured for beds consisting purely of the catalytic and structured packings. However, unlike the two reference beds, the combined bed exhibited a clear upper gas load limit due to a pronounced liquid buildup at the transition from the structured packing to the top element of the catalytic packing section. Also it appeared that the Delft model, with appropriate packing geometry modifications is capable of reliably predicting the preloading region holdup and pressure drop of a hybrid packed bed containing Katapak‐SP.     

错流旋转填料床气相压降的研究

利用空气-水系统对错流旋转填料床的气相压降进行了实验研究。采用因次分析的方法推导出错流旋转填料床气相压降的无因次关联式。结果表明,错流旋转填料床欧拉准数在旋转填料床转速与气速之比(旋流比)小于30时,欧拉准数随旋流比的增大反而减小;当旋流比大于30时,欧拉准数随旋流比的增大而增大。旋流比小于30时欧拉准数与填料层轴向厚度的0.9次方成正比,旋流比大于30时欧拉准数与填料层轴向厚度的0.5次方成正比。湿床旋流比小于30时,欧拉准数随进液量的增大而上升;旋流比大于30时,欧拉准数随进液量的增大而下降。     

The permeability of wood‐chip beds: The effect of compressibility

In this work, we present a methodology to characterise the permeability of a compressible bed of wood chips under mechanical load. We show that under the limiting condition of when the mechanical compression is large in comparison to hydraulic pressure the equations of motion can be linearised and solved to produce an expression approximating the variation in porosity along the length of the bed. We show how this may be used, in conjunction with multiple linear regression to estimate permeability of the bed. In the experimental portion of the work we measure the permeability of a bed of hemlock wood chips at three different kappa numbers κ, and compacted to three different mechanical loads, i.e. compaction pressures p_c. The usefulness of these estimates was then tested by predicting the pressure drop versus flow relationship for conditions outside the range of the linearised solution; the equations of motion were solved numerically with knowledge of the measured permeability. Good agreement was obtained. After accounting for compressibility effects, we find that our correlation has lower flow resistances than the literature correlations. © 2011 Canadian Society for Chemical Engineering     

填料塔压降、液泛研究进展

综述近１０多年来填料塔压降、液泛研究的进展,归纳了压降、泛点关联的三类方法,强调建立数据库的重要性,指出该领域尚有许多有待解决的问题。     

氧化锆催化剂粉末粒度及粒度分布测定的研究

以水作分散介质,用激光粒度测定仪测定了氧化锆催化剂粉末粒度及粒度分布,测试方法快速、准确,测试结果令人满意。     

Prediction of Two‐Phase Frictional Pressure Drop for the Concurrent Gas and Newtonian Liquids Upflow through Packed Beds

Correlations were developed to predict frictional pressure drop for concurrent gas‐liquid upflow through packed beds covering all the three identified flow regimes, i.e. bubble flow, pulse flow and spray flow. The observation that the gas and liquid flow rates have different influences on the two‐phase pressure drop in different flow regimes, was taken into consideration in the development of these correlations. More than 600 experimental pressure drop data from the present study and literature covering a wide range in gas‐liquid systems, flow rates and column packing were used.     

旋转填料床气相压降研究进展

本文概要介绍了旋转填料床的工作原理及结构组成 ,着重讨论了旋转填料床气相压降的实验及理论研究情况 ,分析了气相压降与旋转填料床转速以及气体流量的关系     

填料塔气液并流接触时压降的研究

以内径72 mm的玻璃吸收塔为主体,分别采用Mellapack-250X型金属孔板波纹规整填料以及Dg16塑料阶梯环散堆填料作为传质媒介。以水-SO2作为研究体系,结合气液逆流接触吸收试验对比分析气液并流接触时填料层压降的情况,并分别考察了气相动能因子F和液气比L/V对填料吸收塔气液并流接触时填料层压降的影响。填料层压降随着气相动能因子F的增大呈指数型增长,随着液气比的增加而升高,并流操作时的影响相对逆流操作时变化幅度较小。通过试验结果拟合出相应压降的关联式,为进一步的工艺设计与优化提供相关依据与理论指导。     

旋转填充床除尘技术的研究

采用新型传质分离设备——旋转填充床研究其对发电厂燃煤飞灰的除尘性能。作为一种湿式除尘器，在气量200m^3/h，液量0．5～2．0m^3/h，转速900～l500r／min的条件下，旋转填充床显示出良好的颗粒捕集性能，总效率达99％以上，切割粒径范围在0．02～0．3μm，设备的气体压降较低。讨论了旋转填充床的除尘性能和压降行为，并解释了一些实验现象。     

激光粒度仪法测定HDPE粉末粒度及粒度分布的研究

将HDPE粉末分散在乙醇-水介质中,用激光粒度仪动态测定其粒度及粒度分布。     

Effect of Pore Size and Particle Size Distribution on Granular Bed Filtration and Microfiltration

Abstract

The paper reviews the effect of particle size distribution and pore size distribution on granular bed filter and crossflow microfiltration performance. The experimental results of the granular bed filter with pollen particles in suspension showed that the presence of large particles improved the filter efficiency of smaller particles in suspension. Microfiltration results with bi and tri‐modal latex suspensions showed that the permeate flux and the quality were significantly affected by the particle size and its distribution, especially when the particle size was smaller than the pore size of the membrane. The mathematical model simulation results of granular bed filtration show that media pore size distribution is an important parameter of filtration for the particle removal and pressure drop across the filter.     

流态化造粒过程中喷液方式对粒度分布的影响

对尿基复合肥流态化造粒过程中喷液方式对产品粒度分布的影响进行了初步探讨，提出了粒度归一化数据分析方法，对流态化造粒过程中粒度分布的调节和控制具有一定的指导意义。     

气固流化床中大差异双组份颗粒分级特性的实验研究

为解决清洁汽油生产工艺中存在的能量利用问题,需开发一种能使两种温度不同的催化剂直接混合换热,然后实现催化剂再次分离的组合流化床再生器.在一套φ500 mm×7000 mm的大型冷模装置上对密度相近、粒径差异较大的双组份颗粒形成的气固流化床中稀、密相间颗粒分级特性进行了系统的实验研究,结果表明表观气速、混合颗粒平均停留时间以及混合进料浓度是影响颗粒分级的主要因素,停留时间阈值可用于表征气体分布板形式对分级的影响.利用实验数据回归得到了分级效率的经验模型,模型计算值与实验值吻合较好.     

Experimental Investigation of Pressure Drop Hysteresis in a Cocurrent Gas–Liquid Upflow Packed Bed

Extensive experimental work on hysteresis in a cocurrent gas–liquid upflow packed bed was carried out with three kinds of packings and the air–water system. However, only when packed with small glass beads (f1.4 mm) was the bed pressure drop hysteresis observed. Two more liquids with different liquid properties were employed to further examine the influence of parameters on pressure drop hysteresis. The similarity of pressure drop hysteresis in packed beds was concluded in combination of experimental evidence reported in literature.     

填料层阻力的实验研究

对鲍尔环、阶梯环和多面空心球三种填料的阻力进行了测试,得出了填料层的阻力系数。结果表明：在相同的条件下,鲍尔环阻力最大、阶梯环阻力最小、多面空心球阻力居中。干填料层的阻力系数随空塔气速的增大而减少,湿填料层的阻力系数随空塔气速的增大而增大。利用阻力系数法计算填料层阻力具有简单、准确的优点。     

SiC原料颗粒级配对Si3N4结合SiC复合陶瓷材料的影响

采用SiC粉和Si粉高温氮化反应烧结制备Si3N4结合SiC复合陶瓷材料。研究四种SiC原料粉体(0-1mm、74μm、44μm、和0.5μm)中三种不同粒度不同含量颗粒级配对Si3N4结合SiC复合陶瓷材料的影响。通过X射线衍射仪和扫描电子显微镜对试样的物相和显微结构进行表征,并对试样的耐压强度等力学性能进行测试。结果表明:采用三种SiC较细粉体颗级配且如下组成:74μm的含量为5 wt%,44μm的含量为10 wt%,0.5μm的含量为35 wt%,所制备的Si3N4结合SiC陶瓷材料的基本烧结性能较好,其体积密度为2.43g/cm3,耐压强度为324MPa。     

制备工艺对ATO超细粉体粒度及其分布的影响

采用化学共沉淀法制备锑掺杂二氧化锡（ＡＴＯ）超细透明导电粉体,探讨了制备过程化学反应机理,并研究了反应温度、滴定终点ｐＨ值、掺锑量及煅烧温度对粉体粒度及其分布的影响。另外,用透射电镜（ＴＥＭ）、比表面积（ＢＥＴ）、Ｘ－射线衍射三种不同方法对粉体粒度作了比较表征。     

乙氧基镁催化剂粉末粒度及粒度分布测定的研究

用乙醇做分散介质,用激光粒度测定仪测定四个乙氧基镁催化剂粉末试样的粒度及粒度分布,测试快速、准确。试验结果显示乙氧基镁（德国）催化剂粉末粒度最小,粒度分布集中,在四个样品中质量最好,试验结果令人满意。