气含率与浮选动力学常数的研究

气含率大小是决定浮选柱回收能力和分选效果的重要参数之一,浮选柱内气含率直接决定了气泡荷载上浮矿物的数量与质量,从而决定了浮选过程中精矿的产率和回收率。本文考察了磷矿在充填浮选柱的浮选过程中,表观气体流速和矿浆质量分数对充填浮选柱捕集区气含率的影响。将浮选过程中的气含率与浮选动力学常数相联系,并结合充填浮选柱的工艺特征,推导出了具体的关联式。     

不同浮选设备对选择性絮凝浮选的效果研究

论述了选择性絮凝浮选的原理及影响因素;利用浮选机与浮选柱进行了比较,结果表明,在相同的选择性絮凝浮选条件下,前者的精煤产率和灰分高于后者,而后者的浮选完善指标高于前者。     

基于人工神经网络的充填浮选柱捕集区气含率特性研究

论述了用人工神经网络的方法对影响充填浮选柱捕集区气含率工艺参数(捕集区高径比、气体加入量和起泡剂用量)进行模拟、训练和预测的过程.结合实验结果讨论了各个影响因素对气含率的作用规律,并用基于实验数据建立的人工神经网络对气含率进行预测分析.所建立的神经网络模型的输出值与实验测量值误差在±5％以内,显示神经网络方法预测分析气含率具有较高的适用性,为充填浮选柱的放大研究提供可行的方法.     

SEBS高黏度溶液气液鼓泡塔的流体力学研究

针对SBS加氢反应器开发与设计,以SEBS-1650己烷溶液为液相,采用差压法和床层塌落法研究了气液鼓泡塔中高黏度溶液的流体力学行为,考察了黏度对低表面张力溶液的气含率、大小气泡气含率、大小气泡上升速度和比表面积等因素的影响。结果表明,随黏度增加,大气泡增多,气含率明显降低,塔内流型处于湍流区;由床层塌落曲线确定鼓泡塔内存在三种类型的气泡：大气泡、小气泡及细小气泡,随黏度增加,小气泡与细小气泡逐渐减少;黏度对大小气泡的上升速度略有影响,比表面积随黏度增加而明显降低。根据实验结果给出了大小气泡气含率与平均气含率的计算公式。     

充填浮选柱捕集区气含率的试验研究

通过冷模试验方法考察了充填浮选柱捕集区的气含率，经试验数据回归分析，气含率εｇ＝０．０９６Ｊｇ０．９１（Ｈｃ／Ｄ）－０．１８。并结合漂移通量的理论，确定充填浮选柱的捕集区为近似均匀鼓泡流。     

叶轮自吸式搅拌器的流体力学及传质研究

对叶轮自吸式搅拌器内的流速场、传质系数分布、气泡尺寸以及气含率分布进行了测量，得出了相应的关联式，并作了三维气泡行程的理论分析。阐明了叶轮自吸式搅拌器优于一般鼓泡式搅拌器的原因及其操作特点。     

三相流化床的流体力学特性研究

利用空气、水和玻璃珠颗粒为工作介质,对三相流化床流态化操作的流体力学特性进行了研究,主要研究了气体速度、液体速度、颗粒投加量与气含率的关系,以及气体速度与床层高度及气泡直径的关系。     

浮选柱与浮选机分选煤泥的对比试验研究

通过浮选柱和浮选机对不同煤泥的浮选试验，分析比较了２种浮选方法在分选煤泥时的各自优缺点，证实了浮选柱在浮选细粒细煤泥时具有良好的发选效果；并通过试验，给出了各自最佳的浮选粒度范围。     

浮选柱气泡发生器的研究

通过对新型浮选柱气泡发生器的研究,目的在于对工业生产浮柱中出现的具体问题提供解决的途径,并对静态混合器的研究提供可靠的理论依据。     

采用压力传感技术测量鼓泡床中流体力学参数

引　言鼓泡床以其良好的传热、传质、相间充分接触和高效的可连续操作特性在许多领域得到了广泛应用 .在过去的 4 0多年里 ,人们采用许多测量方法(光导纤维、多普勒测速仪、电导法、压力传感技术 )对鼓泡床中的各种流动行为进行了大量研究 ,由于床层内流动的复杂性以及各测量手段间的差别 ,得出的结论不尽相同[1] ,而且工业反应多数在高温、高压、非透明体系下进行 ,这限制了许多测量技术的应用 .压力传感技术以其适用范围广、所需仪器便宜、耐用、测量结果准确的特点在鼓泡床流体力学参数测量中得到了广泛应用床层塌落法是压力传感技术在鼓泡床流体力学参数测量中的一个重要应用 .Sriram和Mann[2 ] 较早地将其应用于测量鼓泡床中的气含率 ;Fan等[3] 也曾利用此方法测量鼓泡床内的固含率 .前人大都采用压力传感技术测量床层内的平均相含率 ,而采用此方法测量大小气泡分数和气泡上升速度的报道很少 .本文根据前人在此方面的研究成果并结合本实验的特点进行了这方面的研究1　实验装置本实验结合工业对二甲苯氧化反应器的特点设计并建立了其流体力学冷模实验装置 ,如图 1所示 .鼓泡床高 6 6m ,内径 0 3m .在鼓泡床一侧自...     

Double-sensor conductivity probe applied in a flotation system

This study proposed a new approach for measuring bubble size distribution, bubble mean diameter, Sauter mean bubble diameter, and gas holdup using a double-sensor conductivity probe in an air/water two-phase system bubble column. The results for the two-phase system were compared and calibrated using analyses from bubble images taken by a digital camera from the side of the column wall. Good agreement was observed between the two techniques. The same double-sensor conductivity was used in an air/water/solids three-phase system. The conductivity probe captured the change in bubble dynamic behaviour inside the pulp phase; however, the presence of the solids made it more challenging to measure. As a result, the VisioFroth commercial package, using images taken from the top of the froth layer, could be used in conjunction with the double-sensor conductivity probe to show the dynamic evolution of mineralized bubbles from the pulp zone to the froth zone in a flotation process.     

Effect of resistance internal on hydrodynamic behaviours and bubble characteristics in a laboratory-scale bubble column

A novel resistance internal is proposed to optimize the flow field and improve the gas–liquid contact in a co-hydrogenation reactor of coal and vacuum residuum. Local gas holdup, local liquid velocity, and characteristics of the bubble were investigated in a scaled-down laboratory model. The quantitative results showed that the resistance internals could reduce the thickness of the liquid reflux layer by a percentage up to 32% and reduce the difference in the local gas holdup at cross-sections of up to 44%. The Sauter mean diameter of the bubble decreased from 20.30 to 16.00 mm, which aroused the increase in bubble surface area by a percentage of up to 71.9%. The resistance internal promoted the breakup of the bubble with multiple mechanisms and provided diversion to fluid. In this work, improvement at multiple scales was realized, and the technical support for industrial application was provided.     

鼓泡塔中气泡尺寸分布和局部气含率研究

在内径为0.38 m的鼓泡塔中采用双电导探针法对不同通气速率下的气泡尺寸分布和局部气含率进行了实验研究,分析了气泡尺寸的概率密度分布。结果表明:气泡尺寸随轴向高度的增加而增大,随径向距离增加而减小;鼓泡塔中气液流动可分为过渡流域和充分发展流域,在过渡流域气含率随轴向高度增加而增大,在充分发展流域气含率趋于均值,径向局部气含率分布呈抛物线型下降。高气速下气泡尺寸概率密度分布比低气速下宽,且随轴向高度的增加分布变宽。     

Flow characterization of a flotation column

The flow characteristics of a froth flotation column have been experimentally studied using air and aqueous surfactant solutions without the presence of solids. The hold-up behaviours of the bubbly and the froth zones of the column were linked together using the drift-flux model. The ratio of the gas drift-flux, j_gf, to the bubble terminal velocity, V, for both the bubbly and the froth zones was found to be well correlated by the Richardson–Zaki equation:      

筛板结构对多级鼓泡塔中流体力学参数的影响

在外径0.3 m的多级鼓泡塔中采用双探针电导探头考察了筛板结构对鼓泡塔中筛板上下两处流体力学参数的影响,并与无筛板鼓泡塔中流体力学参数进行了对比。研究结果表明:带筛板的鼓泡塔中气含率径向分布规律和无筛板的鼓泡塔相类似,筛板上下二侧的平均气含率随表观气速的增加而增加;在鼓泡塔轴向位置上,筛板下侧的气含率普遍比筛板上侧气含率要高;筛板的孔分布方式对于气含率径向分布有着一定影响,但孔径大小对此影响较小。     

An agitated bubble column for use in potash flotation

A novel, agitated bubble column was designed, constructed and operated for the purpose of potash flotation. This report describes the apparatus and presents some typical results regarding bubble size distribution, gas hold-up and flotation efficiency. It was found that the column produced mean bubble diameters and overall gas hold-ups that could be predicted by empirical correlations presented earlier in the literature for aerated, agitated tanks. The column also achieved both a high percentage recovery ( > 90%) and a high product purity (97%).     

鼓泡塔内空气-醋酸体系流体力学参数的CFD-PBM耦合模型数值模拟

通过二维和三维CFD-PBM耦合模型对空气-醋酸体系中流体力学参数进行数值模拟,采用表面张力修正曳力模型与聚并模型,考察了醋酸浓度对鼓泡塔内气含率、气泡大小分布及轴向液速等参数的影响,与差压法、光纤探针和电阻层析成像技术（ERT）测量的实验数据进行了对比,并讨论分析了气含率和气泡直径等流体力学参数的模拟结果。结果表明,醋酸浓度在70%~80%（质量分数）范围内平均气含率存在最大值,且平均气含率的预测值在±10%误差内,三维模拟结果和ERT实验值吻合较好,说明修正后的模型在不同浓度醋酸体系中具有较好的预测性。     

浆态床鼓泡反应器(SBCR)的研究进展

文章综述了浆态床鼓泡反应器的研究进展。主要介绍了浆态床鼓泡反应器中流型、相含率、气泡动力学等流体力学特性以及操作条件对流体力学特性的影响,并对浆态床鼓泡反应器的发展提出展望。     

Bubble size distribution in a flotation column

The bubbles that were generated in a flotation column were measured. The bubble size distributions were obtained both for air-water and air-water-coal systems. The size distribution pattern was fitted to different equations. It was found that the bubble size distribution in both the flotation and cleaning zones follows the Rosin-Rommler equation used to describe the particle size distribution in crushing. This study indicates that bubbles in the cleaning zone are always larger than those of the flotation zone and finer bubbles are generated when a mixture of frothers is used instead of individual frothers.