气液液三相精馏流体力学性能研究进展

介绍了气液液三相精馏塔板流体力学性能研究的进展情况,讨论了塔板上流动工况、塔板上两液相的混合状况及影响流体力学性能的有关因素。文中提到的许多观点和建议对于优化精馏塔的设计至关重要。     

汽—液—液三相与汽—液两相塔板效率比较

本文通过小型精馏塔及600×150 mm~2矩形模拟塔的实验,对比研究了气(汽)-液两相和气(汽)-液-液三相的塔板效率。并就物系性质(表面张力梯度、液体粘度或分散粘度),两液相体积比,气速及操作工况对传质的影响进行了研究。提出三相传质和两相传质差异的主要因素,得出估算三相精馏塔板效率的关联式。     

复合塔板传质性能研究

在内径为 76mm的玻璃塔内 ,以乙醇 -水为试验物系 ,研究了复合塔板的传质性能。研究表明传质主要在塔板上的泡沫区及填料段的液膜区内进行 ,而淋降区的贡献甚小 ,并研究了影响复合塔板传质性能的诸因素 :塔板开孔率、孔径、填料类型及填料高度等 ,结果对复合塔板的设计具有一定的指导作用。     

气液固三相循环流化床气液传质行为

<正>气液固三相流化床反应器在石油化工、湿法冶金、环境工程和煤的液化等工业领域得到了广泛应用,其基础研究也取得了很大进展.但是,传统三相床主要应用于低液速(U_L<     

高效旋转精馏床的传质性能

以乙醇-水溶液为物系,以不锈钢波纹丝网为填料,在超重力因子为20~120、原料流量0.925~1.851 mol/h、回流比1.5~4.0、原料摩尔分数0.2425、室温进料和常压操作条件下,考察了高效旋转精馏床(HERDB)运行情况与传质性能。结果显示:①高效旋转精馏床运行平稳;②高效旋转精馏床的理论塔板数随超重力因子、原料流量和回流比的增大而增加;③在实验操作条件下,高效旋转精馏床传质单元高度为9.6~65.2 mm。与实验超重力精馏设备相比,高效旋转精馏床的等板高度大于实验室超重力精馏设备,说明存在放大效应。     

立体连续传质塔板在氯丁二烯精馏中的应用

介绍了立体连续传质塔板的结构、原理、特性,并经设计后应用于氯丁二烯-二氯丁烯精馏过程中。改进后的精馏塔,塔顶和塔底高沸物二氯丁烯的质量分数分别降为0．14×10^-3-0．16×10^-3和1％-3％,最高产量达2．175m^3／h,塔板压降减小为10kPa,且操作弹性大、防自聚能力好、传质效率高、能耗低,优于传统的筛板塔。     

提升管三相流化床内的气液传质系数

采用溶氧电极法测定了以牛顿和非牛顿流体为液相的提升管三相流化床的气液传质系数（ｋｌａ）。证明其值受床层流动特性的影响显著，那些能提供高气含率和增大液体循环速率的操作条件也有助于ｋｌａ的提高。通过引入广义雷诺数得出了计算牛顿和非牛顿流体内ｋｌａ的关联式     

规整填料在高压精馏条件下的传质性能

Performance of Mellapak 250Y and 350Y corrugated structured packing in distillation applications at pressures ranging from 0.3 to 2.0MPa is analysed by using HTU-NTU method.These data are obtained in distillation column with 0.15m diameter operated with n-butane/n-pentane system at total reflux.In considering the axial backmixing effects.the height of an overall gas phase transfer unit,HTUOG,is divided into two parts.One part represents the height of an overall gas phase transfer unit,without backmixing, designated as HUTOG,and the other part,designated as the height of a backmixing unit(HBUO),accounts for the backmixing effects.The HTUOG is evaluated from the measured concentration profile of n-butane in liquid phase.The HBUO obtained experimentally is correlated in terms of the properties of the materials being separated and the equivalent diameter of the structured packing.Our result shows that HBUO varies from 0.12 to 0.34m as pressure increases from 1.0 to 1.9MPa.It indicates that the overall efficiency of the structured packing decreas gradually at high pressure,as a result of the vapor backmixing.     

超重力减压间歇精馏的传质性能

以不锈钢波纹丝网为填料,应用超重力减压精馏间歇全回流操作分离乙醇/水共沸物系。考察了进料乙醇质量分数x_f为50%~95%、操作压力P为101.33~11.33kPa和超重力因子β为20.90~130.64时乙醇-水体系的传质性能。实验中设备运行稳定并且单级旋转精馏床传质性能随着超重力因子β的增大先增强后减弱,随着压力P的减小和进料浓度x_f的增加而增强,并在P=11.33kPa时分离高浓度原料时打破共沸点。与相同条件下传统填料塔相比,分离效果明显高于传统塔,且HETP为7.94~14.20mm,仅为传统塔的1/6~1/4,传质性能显著增强。并对能耗进行分析,超重力装置由于自身体积小等优点便于达到所需真空度,能耗降低明显。     

立体传质塔板在乙酸甲酯精馏技改中的应用

选用立体传质塔板取代原乙酸甲酯萃取精馏塔的泡罩塔板进行技术改造,改造后扩产44％,节能约20％,塔压降减小43％,提高了产品质量,降低了原料消耗,技改的设备投资20万元,年增经济效益58．8万元,投资回收期为4个月。     

利用计算流体力学及计算传质的方法研究精馏塔传质效率

It has long been found that the flow pattern of the liquid phase on distillation tray is of great importance on distillation process performance. But until now, there was very few published work on quantitative investigation of this subject. By combining the computational fluid dynamics (CFD) with the mass transfer equation, a theoretical model is proposed for predicting the details of velocity and concentration distributions as well as the tray efficiency of distillation tray column. Using the proposed model, four different cases corresponding to different assumptions of liquid and vapor flowing condition for a distillation tray column were investigated. In Case I, the distributions of velocity and concentration of the incoming liquid from the downcomer and the uprising vapor from the underneath tray spacing are uniform. In Case Ⅱ, the distribution of the incoming liquid is non-uniform but the uprising vapor is uniform. In Case Ⅲ, the distribution of the incoming liquid is uniform but the uprising vapor is non-uniform.In Case IV, the distributions of both the incoming liquid and the uprising vapor are non-uniform. The details of velocity and concentration distributions on a multiple sieve tray distillation column in four different cases were simulated using the proposed model. It is found that the shape of the simulated concentration profiles of vapor and the liquid is quite different from case to case. The computed results also show that the tray efficiency is highly reduced by the maldistribution of velocity and concentration of the incoming liquid and uprising vapor. The tray efficiency for Case Ⅰ is higher than Case Ⅱ or Case Ⅲ, and that for Case Ⅳis the lowest. It also reveals that the accumulated effect of maldistribution becomes more pronounced when the number of column trays increased. The present study demonstrates that the use of computational method to predict the mass transfer efficiency for the tray column, especially for the large one, is feasible.     

Marangoni效应对填料塔精馏传质过程的影响

通过 4种正体系、 5种负体系的精馏实验 ,考察了Marangoni效应对填料塔中传质过程的影响。结果表明 :正体系的气相体积总传质系数KGa与组成无关 ,仅受气相流量 qG 的影响 ,可用关联式KGa =AqGB,和B =0 .94± 0 .0 4表示 ;而对负体系 ,由于Marangoni效应的存在 ,顺着液相流动方向 ,KGa逐渐减小。其关联式为KGa =AqGBMsC,B =1.0 5± 0 .0 4,C =0 .3± 0 .0 5 ,该式的平均误差约为 6%。     

三相连续环流反应器中氧的液相传质过程

在空气-水-玻璃珠三相连续操作环流反应器中,利用动态溶氧方法研究了表观气速(Ug=0.01~0.13 m/s)、进料浆速(USL=0.001~0.011 m/s)、浆相质量固含率(es=0~30%, w)和固相颗粒大小(dp=59, 200 mm)对环流反应器内氧的液相传质性能的影响. 结果表明,在考察范围内,环流反应器传质系数随表观气速增大而增大,受进料浆速变化的影响较小,随浆相固含率增大呈现先增大后减小的趋势,但在高固含率下(es≥10%, w)的影响不显著;随固相颗粒粒径增大而减小. 同时得到了液相体积传质系数的经验关联式.     

三相循环流化床中的气液相界面积和传质系数

采用溶氧法测量了三相循环流化床中液相溶氧浓度的轴向分布,并按轴向扩散模型处理实验数据,优化得到气液体积传质系数kLa,同时用光纤探头测量了体系中的气含率和气泡大小分布,计算得到了气液相界面积a和气液传质系数kL,并研究了主要操作条件(表观气速、表观液速和固含率)对气液传质系数的影响规律.     

新型复合填料塔的传质性能研究

本文提出一种新型的复合填料塔设备,将穿流筛板引入到填料塔中。同普通填料塔相比,复合填料塔优化了液体分布和再分布装置,节省了大量空间,压降低,穿流筛板本身又有优良的传质性能,因此具有比普通填料塔更好的性能。并对复合填料塔传质性能进行了测定和关联,得到了传质性能基础数据,可为复合填料塔的设计应用提供参考。     

蒸馏技术现状与发展方向

分析了精馏传质过程与分离工程的特点 ,介绍了精馏过程的基础理论和过程强化的研究现状。从学科研究的角度 ,提出进行精馏过程非线性、非平衡传质行为和特征的研究 ,是解决设备放大效应的理论基础。而发展精馏技术的科学的工程设计方法 ,需要将过程传递行为与设备结构相结合。并提出了相应的促进措施和研究方法。     

多种塔板组合的板式塔改造技术

介绍综合板式塔技术在重油加氢ＳＳＯＴ装置分馏塔技术改造中的应用,特别是其中采用作者开发的导向梯形浮阀塔板是首次应用于工业装置中,取得了成功。生产实践表明,导向梯形浮阀塔板具有优良的性能,同时应用多种塔板组合的综合板式塔技术,可适应于各种不同的操作工况,值得在板式塔设计和技术改造中推广应用