Research on Pressure Drop Performance of the Packing-Flotation Column

A packing-flotation column was proposed to optimize the flotation environment A research system was established using a 100 mm diameter cyclonic micro-bubble flotation column to study fluid properties. Dry-plate and wetplate pressure drops were studied and the corresponding pressure drop equations developed. The results show that the dry-plate pressure drop of the packing cyclonic micro-bubble flotation column is 10-15 times less than that of the chemical tower, which is principally shown in its relatively small resistance coefficient, ξ = 0.0207. The wet-plate pressure drop is 2-3 times higher than that of the chemical tower, which is largely caused by the separation materials and characteristics of the equipment. With flotation, the greater the pressure drop, the better the flotation environment.     

填料塔体动持液量随高径比而变化的规律

作者首次提出填料塔体动持液量不是均匀分布的，高径比（即填料层高度和塔内直径之比）应是影响动持液量的一个重要参数．采用连续水循环容“量法获得Φ１５瓷拉西环填料在塔径为１３８ｍｍ，空气水系统中不同高径比时体动持液量的实验值．在实验结果的基础上，根据流体力学原理得出填料塔体动持液量随高径比的变化规律．     

圆钢管RPC轴压短柱有限元分析与承载力计算

圆钢管RPC柱可为大跨、高层与高耸建筑、重载工程建设提供性能优越的竖向构件.现有圆钢管RPC轴压短柱承载力计算公式适用于直径不大于152 mm的钢管RPC柱,对大直径钢管RPC柱,计算值偏大.为研究大直径圆钢管RPC轴压短柱承载力计算公式,利用ABAQUS有限元软件,建立了圆钢管RPC轴压短柱分析模型,完成了134种钢管RPC轴压短柱受力全过程分析,研究了RPC相对约束应力与钢管位移曲线的关系,揭示了套箍系数、核心RPC强度等对其荷载-位移曲线的影响规律.结果表明:当套箍系数小于0.5时,钢管RPC柱荷载-位移曲线不存在强化段;当套箍系数大于0.5时,钢管RPC柱荷载-位移曲线出现强化段;当套箍系数达到1时,强化段极限荷载相对于承载力的提升将超过30%,延性更好.相同截面尺寸的圆钢管RPC柱,随核心RPC轴心抗压强度降低,其横向变形系数增大,钢管对核心RPC的约束作用增强.基于试验和数值分析结果,提出了直径达560 mm圆钢管RPC轴压短柱极限承载力计算公式.     

A comparison of anionic and cationic flotation of a siliceous phosphate rock in a column flotation cell

Flotation performance of a de-slimed (-150 + 53 μm)Jordanian siliceous phosphate was evaluated in a batch laboratory flotation column 100 cm high and 5 cm inside diameter. The collector used during anionic flotation was sodium oleate while an amine acetate (AEROMINE 3100C) was used for cationic flotation. Flotation comparison at different collector dosage, superficial gas velocity, and frother concentration showed that the maximum difference in performance between cationic and anionic flotation was obtained with these flotation parameters: 30 × 10 6 (mg/L) frother concentration, 250 g/tcollector concentration, and 3.4 cm/s superficial gas velocity. At these operating conditions amine (cationic) flotation gave 7% higher flotation recovery, a 6% cleaner concentrate grade, and was 6% more efficient at removing silica.     

塑料星型填料解吸传质系数的测定研究

吸收塔径Φ32mm,填料层高度0.45m,填料为金属θ环,解吸塔径Φ100mm,填料层高0.80m,填料为塑料星型填料,研究了空气-氧气在水中的解吸过程,解吸在常温常压下进行,采用溶氧仪测试氧在水中的浓度,根据实验数据得到了液相总体积吸收系数关联式.     

浮选柱反浮选胶磷矿的影响因素

浮选柱是一种高效的细粒物料分选设备,但应用于胶磷矿浮选仍然受诸多因素制约.为考查浮选柱结构特征、工作参数和操作条件等因素对其分选效果的影响,采用试验室浮选柱对贵州瓮安磷矿进行了单一反浮选试验,重点研究了矿浆浓度、药剂用量、筛板充填方式和充气量对浮选柱反浮选效果的影响.结果表明,在磨矿细度为-0.074 mm占88％、矿浆浓度为25％（质量分数）、油酸钠用量为1.8 kg/t、硫酸用量为5 kg/t和充气量为400 L/h时,反浮选的分选效果较好.由于浮选柱可以通过充填筛板来改善其分选环境,因此在较优条件下,其分选效率比用浮选机时高1.57％.     

CFRP-超薄壁圆钢管混凝土轴压短柱承载力的简化计算

基于合理的CFRP筒、钢管和核心混凝土在极限荷载时的应力状态的假设,采用极限平衡法并运用MatLab软件作为运算工具,推导出钢管壁厚小于2mm、径厚比大于120的CFRP-超薄壁圆钢混凝土轴压短柱的承载力计算表达式.结果表明:相对于普通的CFRP-钢管混凝土短柱,CFRP-超薄壁圆钢管混凝土轴压短柱的钢管套箍指标被折减,其承载力有所降低.通过对9个构件的轴心受压试验表明,计算表达式的计算值与试验值吻合良好.     

滴流床中催化剂润湿分率的研究

采用“扰动－响应”技术，在内径０．０５ｍ，床层高度０．６５ｍ，硅胶球填料当量直径分别为７．５ｍｍ和２．５ｍｍ的滴流床内进行了催化剂润湿分率的实验研究［１～４］。提出了阶跃输入、两点检测、以传递函数法估算床层内填料外润湿分率的参数估计方法，并着重分析了实验误差及误差传递方式，研究了气体流率、液体流率及填料直径对润湿分率的影响，给出了计算滴流床反应器内润湿分率的经验关联式。与文献比较，该方法实验易实现，且可获得精度较高的参数估值。     

微钢管轴向导热对对流换热的影响

以氮气为工质,流过内径为168μm、外径406μm微钢管,采用直接通电法进行加热,并使用红外成像仪加红外专用放大镜头测量了在恒定的流量下、不同加热功率以及相同加热功率、不同流量下的微钢管壁面的温度场,获得精确的微管外壁温度分布,同时测量了氮气的进出口温度和流量.根据实验结果分析了微管轴向导热对管内部对流换热的影响.研究表明,在氮气为工质下,微钢管轴向导热导致内部换热的减弱,减少量超过总对流换热量的2%.     

反应精馏合成丁酸异戊酯

在的玻璃填料塔中，以硫酸为催化剂，以丁酸、异戊醇为原料，对反应精馏合成丁酸异戊酯的过程进行了研究，考察了各操作参数对酯化收率的影响。结果表明，采用反应精馏合成丁酸异戊酯的收率为93.6％，比间歇酯化反应酯的收率78.9％高。     

Treatment of Wastewater Containing Heavy Metals Using Dissolved Air Released Flotation Column

A new type of dissolved air released flotation column is developed to treat wastewater containing Cr（Ⅵ） based on advantages of both dissolved air floatation and column floatation. By using a column with a diameter of 50 mm and a specially made dissolved air releaser, micro-bubbles inside the column can be formed. N2H4H2O was used as reductant, AlCl3 as flocculant, C12H25SO3Na（SDS） as surfactant in the experiment. The effects of pH of wastewater, pressure of dissolved air, ratio of return water, and concentration of flocculant and surfactant on the removal efficiency are studied. The results show that the efficiency of dissolved air released flotation column is much higher than that of other approaches after the operation parameters are optimized, with the reduction ratio of Cr（Ⅵ ） in wastewater reaching 98%. So this technique can be widely used in wastewater treatment     

Nanobubble generation and its application in froth flotation(part Ⅰ): nanobubble generation and its effects on properties of microbubble and millimeter scale bubble solutions

A special nanobubble generation system has been developed for evaluating the effect of nanobubble on froth flotation. In this study, an eight-factor five-level Central Composite Experimental Design was conducted for investigating eight important parameters governing the median size and the volume of nanobubbles. These process parameters included surfactant concentration, dissolved oxygen (O2) content, dissolved carbon dioxide gas (CO2) content, pressure drop in cavitation tube nozzle, <50 nm hydrophobic particle concentration, <50 nm hydrophilic particle concentration, slurry temperature and the time interval after nanobubble generation. The properties, stability and uniformity of nanobubbles were investigated. The study of the produced nanobubble's effects on the characteristics of microbubble solutions and millimeter scale bubble solutions was performed in a 50.8 mm column.     

气体吸收传质系数的研究

用吸收塔研究了氨—空气在水中的吸收过程。塔内径75mm,内装直径8mm 的拉西环,填料层高度为150mm,气体中氨的浓度低于10%(体积)。吸收温度和压力分别为20℃和1atm,依据实验数据,得到了体积吸收系数的经验公式。     

Experimental study on microcapsule fluid oscillating heat pipe

In this experiment,a four-turn oscillating heat pipe(OHP)is made of copper tube with an inner diameter of 1.3mm,and an outer diameter of 2.5mm.A series of experiments are performed to investigate the startup characteristics of OHP,and the effects of different working fluids(FS-39E microcapsule fluid,pure water,ethanol),different liquid filling rates(40%—80%)on the heat transport capability of OHP in vertical bottom heat mode.The results show that the startup of OHP is relative with liquid filling rate,therm...     

用胶质气体泡沫从废水中浮选Cu(Ⅱ)的实验研究

采用胶质气体泡沫作为浮选载体对含Cu(Ⅱ)模拟废水进行了浮选分离实验．在浮选柱中装入特定浓度的含Cu(Ⅱ)模拟废水，用表面活性荆十二烷基磺酸钠(SDS)制备胶质气体泡沫，将胶质气体泡沫引入到浮选柱，然后通入压缩空气形成常规柱浮选气泡完成浮选过程．此外，还考察了pH值、SDS用量和Cu(Ⅱ))初始浓度对分选效果的影响．实验结果表明，采用胶质气体泡沫和常规柱浮选结合的方法对含Cu(Ⅱ)模拟废水的铜离子去除率可达99％以上。     

CFD model simulation of bubble surface area flux in flotation column reactor in presence of minerals

Bubble surface area flux(S_b) is one of the main design parameter in flotation column that typically employed to describe the gas dispersion properties, and it has a strong correlation with the flotation rate constant. There is a limited information available in the literature regarding the effect of particle type,density, wettability and concentration on Sb. In this paper, computational fluid dynamics(CFD) simulations are performed to study the gas–liquid–solid three-phase flow dynamics in flotation column by employing the Eulerian–Eulerian formulation with k-e turbulence model. The model is developed by writing Fortran subroutine and incorporating then into the commercial CFD code AVL FIRE, v.2014.This paper studies the effects of superficial gas velocities and particle type, density, wettability and concentration on Sband bubble concentration in the flotation column. The model has been validated against published experimental data. It was found that the CFD model was able to predict, where the response variable as indicated by R-Square value of 0.98. These results suggest that the developed CFD model is reasonable to describe the flotation column reactor. From the CFD results, it is also found that Sb decreased with increasing solid concentration and hydrophobicity, but increased with increasing superficial gas velocity. For example, approximately 28% reduction in the surface area flux is observed when coal concentration is increased from 0 to 10%, by volume. While for the same solid concentration and gas flow rate, the bubble surface area flux is approximately increased by 7% in the presences of sphalerite.A possible explanation for this might be that increasing solid concentration and hydrophobicity promotes the bubble coalescence rate leading to the increase in bubble size. Also, it was found that the bubble concentration would decrease with addition of hydrophobic particle(i.e., coal). For instance, under the same operating conditions, approximately 23% reduction in the bubble concentration is predicted when the system was working with hydrophobic particles. The results presented are useful for understanding flow dynamics of three-phase system and provide a basis for further development of CFD model for flotation column.     

射流浮选柱气泡发生器及其充气性能的研究

根据射流泵原理设计了一种浮选柱气泡发生器，并对其充气性能进行了试验，研究了气泡发生器结果参数、流体压力、负压与柱内含气率的关系；探讨了浮选过程中浮选药剂浓度、矿浆浓度变化对含气率的影响．结果表明：气泡发生器的射流面积比对含气率有较大影响，最佳面积比为6～10；含气率随压力增高而增加，压力升到一定程度后，含气率趋于平稳；当气泡发生器吸气室负压达到一定数值后，含气率也将趋于饱和；随起泡剂用量加大，含气率呈上升趋势；随矿浆浓度的增加，含气率则呈下降趋势．研究结果为射流浮选柱气泡发生器的设计和结构优化提供了依据。     

气液并流通过波纹筛板填料的流体力学性能

脉冲流是堆叠筛板填料中的一种特殊流型，因其具有较高的传质传热效率而受到关注。本文从强化气液相互作用、扩展脉冲流操作区域的角度提出波纹筛板填料，并通过实验研究了三种规格波纹板填料中的两相流压降特性和脉冲流行为。结果表明，与普通筛板填料相比，波纹板填料中脉冲流的操作范围显著扩展、脉冲流强度也同时增强；突出特点是，脉冲流的出现有一起始液量，且该起始液量随着孔径的减小而减小，筛孔较大的两种波纹板填料中出现脉冲流的起始液量相较于普通筛板显著降低，三种波纹筛板脉冲流操作区域的上限气量均显著提高。波纹板填料中两相流压降的变化以及操作参数、孔径及开孔率等结构参数的影响规律类似于普通筛板填料，两相流压降随着气、液流量的增加而增大，随着板数的增加呈线性增加关系；筛板孔径和填料开孔率的减小都导致压降的增加，二者影响的显著性是相对的且与两相流量有关；由于流动不规则性增强，波纹板单板压降同比高于普通筛板。综合实验数据，提出了波纹筛板填料的干、湿板阻力系数关联式和脉冲流操作区域的上、下限气、液相雷诺数关联式，其预测值与实验结果相对偏差均在15%以内，可供波纹板堆叠填料的应用设计参考。     

SiC-水纳米流体在微小通道中的流动和换热特性

为了解决传统换热工质导热系数和传热性能不高的问题,以Si C-水纳米流体为工质,研究了不同体积分数(0.001%、0.005%、0.01%、0.1%、1%)的Si C-水纳米流体在多孔微通道平行流扁管中的单相流动和换热特性.该扁管矩形通道的水力直径为2.08 mm,实验Re大约为150~5 200.研究结果表明:随着体积分数的增加,纳米流体的Nu呈现先增长后下降的趋势;体积分数为0.01%的Si C-水纳米流体在Re≈5 200时,Nu增长最大,增长率达到80.8%;纳米流体起到强化换热效果的同时,伴随着阻力增加.     

内置分段式弹簧换热管内流场的数值模拟

针对内置弹簧换热管在强化传热过程中产生较大阻力的问题,提出了一种插入分段式弹簧的方法,并通过Fluent软件对内置不同长度的弹簧换热管某一截面处的流动特性进行数值模拟,分别取每段弹簧的长度分别为50 mm、100 mm、150 mm、200 mm,得到了在内置不同长度弹簧的换热管内某一截面处的速度场;然后分别取不同丝径和圈径的分段式弹簧,对换热管内某一截面的流体径向速度场进行数值模拟,研究弹簧的丝径与圈径对强化传热的影响.结果表明:在换热管两端插入分段式弹簧使得管内流体径向速度提高了2~3倍,加快了管内壁区域流体的流动,使得边界层变薄,不仅加强了边界层流体的扰动,而且一定程度上降低了流体流动的阻力,从而提高了换热效率.在雷诺数相同时,内置分段式弹簧换热管相对于光管Nu数提高了2~4倍;随着丝径和圈径的增大,强化传热效率得到提高而流动阻力随着相应增加.