Prediction of dispersed phase holdup in pulsed disc and doughnut solvent extraction columns under different mass transfer conditions

Using experimental data from a number of pulsed disc and doughnut solvent extraction columns, a unified correla- tion for the prediction of dispersed phase holdup that considers the effects of mass transfer is presented. Pulsed disc and doughnut solvent extraction columns （PDDC） have been used for a range of important applications such as ura- nium extraction and nuclear fuel recycling. Although the dispersed phase holdup in a PDDC has been presented by some researchers, there is still the need to develop a robust correlation that can predict the experimental dispersed phase holdup over a range of operating conditions including the effects of mass transfer direction. In this study, dis- persed phase holdup data from different literature sources for a PDDC were used to refit constants for the correlation presented by Kumar and Hartland lind. Eng. Chem. Res.,27 （1988）,131-138] which did not consider the effect of col- umn geometry. In order to incorporate the characteristic length of the PDDC （i.e. the plate spacing）, the unified cor- relation for holdup proposed by Kumar and Hartland based on data from eight different types of columns [Ind. Eng. Chem. Res.,34 （1995） 3925-3940] was refitted to the PDDC data. New constants have been presented for each hold- up correlation for a PDDC based on regression analysis using published holdup data from PDDCs that cover a range of onerating conditions and nhwical nronerties and consider the direction of mass transfer.

Extraction of Caprolactam from Aqueous Ammonium Sulfate Solution in Pulsed Packed Column Using 250Y Mellapak Packings

Liquid-liquid equilibrium (LLE) data of water-caprolactam-benzene-(NH4)2SO4 system at 303 K were measured for extraction of caprolactam from aqueous ammonium sulfate solution. The influence of fluid flow rate, pulsation intensity on flooding velocity and mass transfer was studied for extraction of caprolactam from ammonium sulfate solution in a laboratory pulsed packed column. The flooding velocities and overall apparent height of a transfer unit were given under various operation conditions. An industrial column developed based on above study is operated well. The scale-up effect is discussed.

Design aspect of a novel L-shaped pulsed column for liquid–liquid extraction applications: Energy consumption and the characteristics velocity concept

This article deals with the evaluation of the consumption of energy for a steady state solvent extraction in a novel L-shaped pulsed sieve-plate column, which is highly required for design and optimization of the periodic flow processes for industrial applications. In this regard, a comprehensive evaluation on the energy consumption in case of a pulsed flow for three different chemical systems is conducted and besides the influence of pulsation intensity, the effect of geometrical parameters including the plate spacing and the plate free area is investigated as well. Moreover, the concept of characteristic velocity models at flooding points is evaluated with respect to the variation of pressure drop along the column at different operational conditions.

Axial mixing and mass transfer characteristics of pulsed extraction column with discs and doughnuts

The axial mixing is a key factor for design and scaling up of the pulsed extraction column which has strong influence on the mass transfer performances of the pulsed extraction column with discs and doughnuts. A steady-state concentration profile measurement was used to evaluate the mass transfer and axial mixing coefficients for the nitric acid/water/30%TRPO (in kerosene) system in the pulsed extraction column with the diameter of 38 mm on the condition of the TRPO-kerosene solution as the continuous phase and the flow ratio of 1∶1. Experimental results indicate that Ey evaluated by the experiments is in good agreement with that given by Burratti’s correlation; the axial mixing is far smaller for the continuous phase than that for the dispersed phase. However the empirical correlation for HOX is only given based on the present data.

近场脉冲型地震作用下附加支撑双柱式摇摆桥墩的抗震性能研究

为了解决摇摆桥墩承载力和耗能能力不足的问题,该文提出一种附加人字形支撑的双柱式摇摆桥墩结构,支撑为纯耗能支撑或自复位耗能支撑,支撑通过连接装置安装在双柱式摇摆桥墩的盖梁和承台之间。为了研究新型附加人字形支撑双柱式摇摆桥墩的抗震性能,对其进行拟静力分析,将双柱式现浇桥墩和双柱式纯摇摆桥墩作为对比模型,研究附加纯耗能支撑和自复位耗能支撑双柱式摇摆桥墩的滞回性能;分别对这四种桥墩结构进行动力时程分析,探究这四种桥墩在近场对称脉冲、近场非对称脉冲和远场无脉冲地震动作用下的动力响应。研究结果表明:附加支撑的双柱式摇摆桥墩中的墩柱仍具有摇摆机制,可有效避免墩身出现塑性铰发生严重的损伤破坏,同时附加的支撑可以显著提高桥墩的承载能力和耗能能力,有效降低桥墩结构的位移响应,特别是自复位耗能支撑还可额外为桥墩提供自恢复力,有效提高结构的抗震性能。

A data-driven model of drop size prediction based on artificial neural networks using small-scale data sets

An artificial neural network(ANN)method is introduced to predict drop size in two kinds of pulsed columns with small-scale data sets.After training,the deviation between calculate and experimental results are 3.8%and 9.3%,respectively.Through ANN model,the influence of interfacial tension and pulsation intensity on the droplet diameter has been developed.Droplet size gradually increases with the increase of interfacial tension,and decreases with the increase of pulse intensity.It can be seen that the accuracy of ANN model in predicting droplet size outside the training set range is reach the same level as the accuracy of correlation obtained based on experiments within this range.For two kinds of columns,the drop size prediction deviations of ANN model are 9.6%and 18.5%and the deviations in correlations are 11%and 15%.

湿法冶金领域脉冲萃取技术与设备研究进展

脉冲萃取塔作为一种高效的液液萃取设备,是湿法冶金技术塔式萃取设备开发的重要方向之一。系统综述了脉冲萃取塔的开发过程,重点探讨了传递过程规律的研究、数学模型的构建,以及计算流体力学(CFD)在设备开发中的应用。回顾了脉冲萃取塔操作与结构参数对流体力学以及传质性能的影响,揭示了传质、传动量等过程中的规律性和影响因素。在此基础上,介绍了CFD模拟和其他计算技术的应用,进一步优化塔的设计与性能。最后,总结了脉冲萃取塔内构件和塔型式的改进方案,指出了未来研究的方向和潜在应用场景,旨在为今后的研究与应用提供有价值的参考。

脉冲萃取柱专用智能控制器研究

脉冲萃取柱是核燃料后处理厂中的关键设备,其运行情况关系萃取的效果以及全厂的安全,监测脉冲萃取柱的运行情况至关重要。该文设计研究智能脉冲萃取柱专用控制器,搭建专属于脉冲萃取柱的独立控制器,控制器具有独立计算、存储等功能,能够实时监测脉冲萃取柱的运行情况,搭载自适应模糊PID控制方法,能够自适应调节控制萃取柱界面,并具有故障诊断、远程控制等功能,能够为脉冲萃取柱提供更全面的测控需求,提升了脉冲萃取柱的运行效率并为其安全平稳运行提供支持。

Creep properties and resistivity-ultrasonic-AE responses of cemented gangue backfill column under high-stress area

To investigate the creep and instability properties of a cemented gangue backfill column under a highstress area,the uniaxial compression creep tests were conducted by single-step and multi-step loading of prismatic samples made of cemented gangue backfill material(CGBM)under the high stressstrength ratio.The creep damage was monitored using an electrical resistivity device,ultrasonic testing device,and acoustic emission(AE)instrument.The results showed that the CGBM sample has a creep hardening property.The creep failure strength(CFS)is slightly larger than the uniaxial compressive strength(UCS),ranging in ratio from 108.9%to 116.5%.The instantaneous strain,creep strain,and creep rate increase with increasing stress-strength ratio in the single-step loading creep tests.The instantaneous strain and creep strain decrease first and then increase during the multi-step loading creep process.The axial creep strain of the CGBM column can be expressed by the viscoelastic-plastic creep model.Creep instability is caused by the accumulation of strain energy under multi-step loading and the continuous lateral expansion at the unconstrained middle position during the creep process.The creep stability of a CGBM column in a high-stress area can be monitored based on the variation of electrical resistivity,ultrasonic pulse velocity(UPV),and AE signals.

Study on arc characteristics and behavior of metal transfer in pulse current flux-cored arc welding of mild steel

The variation in arc characteristics and behavior of metal transfer with the change in pulse parameters has been studied by high speed video camera during pulse current flux-cored arc weld deposition.A comparative study of similar nature has also been carried out during flux-cored arc weld deposition in globular and spray transfer modes.The effect of pulse parameters has been studied by considering their mean current and arc voltage.The arc characteristics studied by its root diameter,projected diameter and length,and the behavior of metal transfer noted by the metal transfer model and the droplet diameter have been found to vary significantly with the pulse parameters.The observation may help in understanding the arc characteristics with respect to the variation in pulse parameters which may be beneficial in using pulse current FCAW to produce desired weld quality.

近场脉冲型地震动横向激励下附加SCEB双柱式桥墩结构易损性分析

为了研究桥墩结构的震后功能可恢复性,针对附加自复位耗能支撑(self-centering energy dissipation braces,SCEB)双柱式桥墩结构进行基于增量动力分析方法的地震易损性分析,采用最大侧移率和残余侧移率作为性能指标,系统探讨其在近场脉冲型地震动作用下的失效概率.为了对比分析,同时选取60条远场无脉冲型地震动记录对附加SCEB桥墩结构进行了易损性分析.结果表明:在小震作用下,SCEB仅为桥墩结构提供刚度和承载力,在大震作用下还可提供耗能能力,同时可以提供良好的自复位能力;附加SCEB可有效降低桥墩结构在近场脉冲型地震动作用下的失效概率(最大侧移率和残余侧移率),特别是残余侧移率;附加SCEB桥墩结构在近场脉冲型地震动作用下的失效概率大于远场无脉冲型地震动作用下的失效概率.自复位耗能支撑可有效减小桥墩结构的失效概率,提高桥墩结构的抗震性能.

一种炭柱调压器低频脉冲扫描检测电路设计

炭柱调压器是飞机电源系统稳定发电机输出电压的关键部件,该设备的性能好坏对飞行安全有着直接影响。针对炭柱调压器故障检测和维护难度大的问题,该文进行“炭柱调压器炭柱粘连故障的低频脉冲扫描检测电路”的设计和应用,实现对疑似故障炭柱调压器进行快速、有效、准确的故障检测,以筛选出故障设备和非故障设备,避免对非故障调压器实施误维修,减轻航空调压器的修理工作强度。该文针对电磁铁的低频脉冲电压驱动电路,炭柱伸缩时阻压转换电路,炭柱电阻电压采集电路进行设计,并将它们连接在一起构成总电路,最终获得基于低频脉冲扫描的炭柱调压器故障检测电路,实现对调压器故障的高效维修。

工艺参数对定间距电沉积微镍柱表面形貌的影响

电沉积过程中电极极间距的恒定可以有效地提高电沉积的沉积效果,研究了脉冲电压幅值、脉冲占空比和负向脉冲电流对微镍柱表面形貌的影响。为了探索当极间距恒定后脉冲电压幅值、脉冲占空比和负向脉冲电流对微镍柱表面形貌的影响,采用扫描电子显微镜和体式显微镜观测微镍柱表面形貌,采用COMSOL Multiphysic软件对电流密度和电场强度进行仿真验证,研究各个工艺参数对微镍柱表面形貌的影响,对比在相同参数下定间距与变间距沉积、有无负向脉冲电流的微镍柱的表面形貌。结果表明:在定间距下,电压在4.1~4.7V时,可以得到圆柱度较好且平均直径在47~100μm的微镍柱;在电压为4.7V时,微镍柱呈尖锥状,无分叉现象和瘤状沉积,随着电压的增加,沉积速率从0.33μm/s增长到0.7μm/s,优化后的负向脉冲电流参数为电压2V,频率0.5kHz,占空比60%,单个周期内正负脉冲个数比值5:1。恒定极间距可以改善微镍柱呈堆叠状沉积的现象,增加负向脉冲可以对微镍柱实现一定的修整效果,同时起到消溶沉积层的微毛刺、微凸起和枝状晶作用。

速度脉冲强震下偏心重力柱-核心筒体系的抗震性能研究

研究速度脉冲强震和结构偏心双重不利对新型重力柱-核心筒结构体系地震响应的影响。以地震模拟振动台试验为基础,采用CANNY软件校验参数设置合理性。设计不同高度质量偏心重力柱-核心筒结构,分别选取10条速度脉冲和10条非速度脉冲地震记录作为输入,采用CANNY软件对偏心体系进行动力时程分析,系统地研究了速度脉冲地震和偏心率对结构地震响应的影响规律。结果表明:脉冲地震工况下各偏心体系的弹性和弹塑性层间位移角、剪力、扭矩、扭转角均显著高于非脉冲地震工况对应值。弹塑性工况比弹性工况增大效应明显,变形增大效应比力增大效应更为显著。随着偏心率增大,弹性和弹塑性层间位移角、扭矩和扭转角均增大,层间剪力则呈现减小趋势。增量动力分析结果亦表明,偏心和速度脉冲地震效应均会显著增大层间位移角。建议在新型重力柱-核心筒结构的抗震设计中,应充分考虑速度脉冲地震和偏心对其地震响应的耦合影响。

脉冲筛板萃取塔CFD-PBM模型研究

脉冲筛板萃取塔是核工业等领域中最常用的萃取设备之一,为深入了解脉冲筛板萃取塔中两相流行为规律,使用CFD-PBM模型对脉冲筛板萃取塔中由有机相(30%TBP-正十二烷)、水相(HNO_(3)水溶液)组成的体系进行两相流过程模拟分析,模拟结果与实验数据吻合较好,分散相存留分数和Sauter平均液滴直径的相对偏差仅为8.28%和5.54%;随脉冲速度增加,Sauter平均液滴直径减小,液滴直径分布更均匀,分散相存留分数增加,特性速度减小;两相表观速度对液滴直径影响较小,分散相表观流速增加有利于提高分散相存留分数,而连续相表观流速影响不大;发生液泛时分散相液泛表观速度随连续相液泛表观速度增大而减小,随脉冲速度增加液泛通量先增后减,存在极值。

拉索方法对脉冲折流板萃取柱存留分数的预测

为了获得适用性好,且便于分析的脉冲折流板萃取柱内存留分数变化的预测方程,本文使用拉索回归方法拟合分析了通过体积置换法测试的脉冲折流板萃取柱中煤油-水体系下的脉冲强度、分散相流速和连续相流速3个操作参数对存留分数的影响。并对比分析了相关文献中的多组经验关系式重新拟合的方程与使用拉索回归方法拟合出的多元二次形式的预测方程。结果表明:拉索回归方法拟合出的预测方程能够很好的贴合实验数据,并且通过分析该方程对应3个操作参数的偏导数,定量地分析不同参数在具体的操作范围内对存留分数的影响大小。本文方法同时能够很好地适用于其他文献的数据当中,拟合结果与实验数据的平均相对误差都在20%以内,能够简单直观地分析各个参数对存留分数的作用大小。

双向速度脉冲地震下偏心重力柱-核心筒结构的弹塑性地震响应研究

研究速度脉冲地震和结构质量偏心综合不利条件下新型重力柱-核心筒结构体系的弹塑性反应规律。选取速度脉冲和非速度脉冲地震加速度记录各10条,进行地震动双向输入,采用结构非线性分析软件CANNY进行有限元数值分析,研究脉冲型地震和结构质量偏心对新型体系弹塑性地震反应的影响。分析结果表明,速度脉冲型地震作用下各结构的层间位移角、层间剪力和层间扭转角显著高于非速度脉冲地震下的相应值。质量偏心对结构弹塑性抗震需求影响显著,层间位移角和层间扭转角都随着偏心率的增大而增大,而层间剪力则随偏心率的增大呈减小趋势。建议在重力柱-核心筒结构设计中应重视速度脉冲地震和结构偏心的耦合不利影响。

脉冲型地震下竖向不规则重力柱-核心筒结构的弹塑性地震响应

研究了速度脉冲型地震作用和结构竖向不规则双重不利条件对结构弹塑性地震反应的影响。设计了20层和30层的新型重力柱-核心筒典型结构,通过改变底层刚度得到一系列竖向不规则结构。分别选取10条速度脉冲和10条非速度脉冲地震记录,采用CANNY软件对竖向不规则重力柱-核心筒结构进行弹塑性动力时程分析,研究速度脉冲效应和竖向不规则对结构弹塑性地震响应的影响规律。结果表明,速度脉冲地震下结构层间剪力、层间位移和倾覆力矩均明显高于非速度脉冲地震下的对应值;竖向不规则对结构弹塑性抗震需求影响显著,层间位移角随着竖向不规则比率的减小而增大,层间剪力和倾覆力矩则呈略微减小的变化趋势。建议在新型重力柱-核心筒结构设计中应考虑速度脉冲地震和结构竖向不规则的耦合影响。

吹气法在线测量脉冲萃取柱参数研究

用吹气法在线测量脉冲萃取柱参数。结果表明 :两相界面测量的偏差在± 4mm以内 ,脉冲频率测量的相对偏差在 2 %以内 ,存留分数测量的相对偏差在± 5%以内。由信号曲线得到的参数S与脉冲腿中的表观脉冲振幅之间存在较好的线性关系 ,脉冲柱内真实振幅与表观振幅和频率比值之间也存在相关性较好的线性关系。

脉冲萃取柱中正辛醇-硝酸体系流体力学性能研究

研究了喷嘴板脉冲萃取柱中正辛醇 - 0 5mol/L硝酸体系的液泛通量、分散相存留分数等流体力学特性。用改进的Pratt公式对两相流体力学参数进行了关联 ,得到水相连续时的n值为1 15,有机相连续时的K值为 5 6 4。特性速度可用下述经验公式关联 :Vo(Vo′) =11.7e- 0 .6 93Af。有机相连续时柱内液滴以聚集为主 ,水相连续时柱内液滴以分散为主。在相同的脉冲强度下 ,该体系水相连续时液泛通量较小 ,有机相连续时液泛通量较大。经验公式计算得到的水相连续时的液泛通量与实验值的相对误差在± 15%以内。