【作者】 王厚林；

【导师】 张卫东；

【作者基本信息】 北京化工大学 ， 化学工程与技术， 2010， 硕士

【摘要】 中空纤维更新液膜(HFRLM)技术是一种新型的同级萃取反萃技术,具有传质阻力小、传质速率高、操作简单、无二次污染等优点,在重金属废水处理、发酵产物原位提取等方面有较大的应用潜力。作为液膜过程重要的支撑体,中空纤维膜丝结构、中空纤维管内流体的流动状态等对中空纤维更新液膜过程的传质性能有重要的影响。以Cu(II)-LIX984N/煤油-H2SO4为体系,考察了中空纤维膜丝内径、膜丝壁厚等结构参数在不同管壳程流速、油水比等条件下对中空纤维更新液膜过程传质性能的影响。结果表明,中空纤维更新液膜过程的传质通量随膜丝壁厚的增大而降低,随膜丝内径、油水比、管程料液流速的增大而升高。且当膜丝内径和油水比较大时,中空纤维更新液膜过程的更新强化作用更加明显。在显微镜和摄像机的辅助下,让油—水两相流充分混合后通过水平纤维管,对不同内径的疏水性聚偏氟乙烯中空纤维膜丝管内两相流的流动状态进行了可视化研究。结果表明,液滴粒径大小和粒径分布幅度均随中空纤维膜丝内径和两相流平均流速的增大而增大。通过可视化研究结果,拟合得到了液滴Sauter平均径、膜丝内径和流速的关系式,‘并最终获得了疏水性聚偏氟乙烯中空纤维膜丝管内LIX984N/煤油—去离子水体系的两相流型图。以阻力串联模型为基础,假设膜丝管内存在更新传质过程和萃取传质过程,采用更新传质关联式和管内连续相、分散相传质关联式计算管程分传质系数,并进而建立了中空纤维更新液膜过程的传质模型,模型计算值与实验值吻合较好。更多还原

【Abstract】 Hollow fiber renewal liquid membrane (HFRLM) techniques is a new type of simultaneous extraction and stripping processes in the same stage. It has many advantages, such as low mass transfer resistance, high mass transfer rate, simply operate, non secondary pollution, long-term stability, etc. It has great application potential in the following industrial field, including heavy metal wastewater treatment and in-situ fermentation product recovery, etc. In HFRLM process, the core part is the membrane module. Moreover, the hollow fiber in the module play an imoprtant role in the whole process, because the hollow fiber membrane structures and the fluid flow in the fiber have great influence on the mass transfer performance.In this work, copper sulfate solution was used as feed phase, LIX984N dissolved in kerosene was choosen as membrane phase and sulfuric acid is used as stripping phase. Effects of inner diameter and thickness of hollow fiber membrane, tube side and shell side velocity, oil-water ratio on the HFRLM process performance were investigated. Results indicated that the better performance of HFRLM in our study could be obtained in case of the thinner fiber thickness, the larger fiber inner diameter, the larger oil-water ratio and the larger tube velocity. Besides, the mass transfer enhancement increased with increasing hollow fiber inner diameter and oil-water ratio.The visualization research on oil-water flow in horizontal PVDF hollow fiber with different inner diameter was done by using microscope and high speed camera. Experimental results indicated that the mean and variance of droplet size distributions increased with increasing fiber inner diameter and velocity. The correlation for calculating the Sauter mean diameter of various hollow fiber inner diameter and velocity has been established. And, the flow pattern of the system of LIX984N dissolved in kerosene and deionized water was obtained.Based on the resistance in series model and assuming the renewal mass transfer and extract mass transfer exist in the tube, the mass transfer model of HFRLM process was founded. The model results were in good agreement with the experimental data.更多还原