共查询到19条相似文献,搜索用时 140 毫秒
1.
2.
3.
对丝网BX、陶瓷BY、不锈钢板波纹填料及环矩鞍填料的传质性能和流体力学性能进行了测定,得到了三种规整填料全回流条件下较为简明的压降关联式,探讨了一些因素对各型填料精馏特性的影响。 相似文献
4.
5.
6.
气液两相不均匀流动是造成填料塔传质效率下降的主要原因之一.采用计算流体力学方法,定量分析规整填料内气液两相流动对传质效率影响的研究尚未见文献报道.从Navier-Stokes方程出发,首先建立了考虑气液之间相互作用的CFD计算模型,定量描述了填料片内的气相流场分布.在此基础上,结合文献中提出的液相结点分布模型及一些经典的传质理论,初步提出了适用于定量计算金属板波纹填料传质效率的耦合型算法,并对规整填料内的传质效率进行了计算,模型结果与实验值吻合较好.为规整填料传质效率的定量研究提供了新的方法和思路. 相似文献
7.
综述了规整填料传质性能的计算方法和模型,并对这些模型的理论基础和适用条件进行了分析和比较。归纳了近年来对于传统规整填料传质模型的修正和扩展,并对影响传质性能的有效比表面积的经验关联式进行了讨论,指出了规整填料传质性能研究方面进一步的探索方向和应改进的若干问题。 相似文献
8.
规整填料精馏塔的设计计算 总被引:1,自引:0,他引:1
通过大量的文献调研,比较了规整填料精馏塔和板式塔的优缺点,对规整填料精馏塔内压降、传质及液泛时压降的计算公式进行了比较,总结出设计计算规整填料精馏塔的步骤与方法,为规整填料精馏塔的应用提供了基础。 相似文献
9.
引 言复合规整填料是由两种比表面积相差较大的规整填料复合而成 ,与普通规整填料相比 ,具有操作弹性大的优点 ,特别适用于气液通量大的操作场合 ,如原油减压蒸馏等 .复合规整填料内液相混合行为复杂 ,对传质过程有重要影响 .但到目前为止 ,人们仅对散堆填料塔中液相混合有较多的研究[1~ 6] ,而且不很成熟 ;对规整填料塔及复合型规整填料塔的研究就更不足 .为了促进复合型规整填料的开发和应用 ,本文对复合规整填料Mellapak(12 5X +2 5 0Y)中的液相混合进行了研究 .1 模 型目前常用的描述填料塔中液相混合行为的模型是扩散型… 相似文献
10.
11.
The Marangoni effect on the mass transfer coefficient of falling films was investigated on inclined stainless‐steel plates to elucidate the influence on the mass transfer performance of structured packing surfaces. Desorption of ethanol from water generated the Marangoni effect in the liquid phase while the process of oxygen desorption from water was proceeded. The enhanced liquid phase mass transfer by the Marangoni effect was found to be related to the ethanol concentration in the liquid, inclination of the plate, and liquid flow condition. A generalized correlation was proposed to predict the effective enhancement factor of the system incorporated with the Marangoni effect. 相似文献
12.
介绍了利用激光诱导荧光技术(LIF)测量规整填料内的液体分布的实验方法,实现了液体分布的可视化,得到了液膜厚度和持液量等定量信息。利用LIF技术分别测量了3种物系在750Y型规整填料的实验装置内的液体分布。结果表明,表面张力和黏度都对填料表面上的液体分布有影响,但表面张力对液膜厚度和持液量的影响较大,是主要影响因素。 相似文献
13.
Electrochemical gas absorption or biotechnical purification processes using structured packing as electrode or as biological support, respectively, may operate in bubble columns in presence of suspended solids. In both systems the knowledge of mass transfer rates from the liquid to the packing is important for the design of equipment. In the present investigation, the fluid dynamic behavior of a simple bubble column and a bubble column containing small size particles, both in presence of structured packing, was studied. Furthermore, mass transfer coefficients between the liquid and the structured packing were obtained by the electrochemical method. The influence of physical properties of the liquid phase, gas flow rate, kind and concentration of the suspended particles on both gas holdup and mass transfer was investigated. Correlations of the experimental data of mass transfer using dimensionless groups were derived and compared to previous correlations. Similarity with a heat transfer expression already used in two-phase systems was found. 相似文献
14.
Francisco Rendtorff Birrer 《Chemical engineering science》2004,59(20):4385-4392
Gas holdup in bubble columns containing structured packing was determined for varying liquid phase viscosity and different construction materials of the packing. Three columns, containing packing made from smooth nickel plate, perforated nickel plate and plastic sheets, respectively, were tested. The gas holdup in a column with no internals was also measured for comparison purposes. The effect of viscosity on gas holdup was studied by using water, aqueous glycerol and aqueous CMC solutions as the liquid phase; some of the solutions showed non-Newtonian behavior.The experimental results of gas void fraction were correlated in terms of superficial gas velocity and liquid viscosity through a simple homographic expression. The geometric characteristics of the structured packings were found to influence gas holdup, thus yielding slightly different equations for each structured packing. This effect is discussed in detail. Nevertheless, for engineering purposes a single equation representing all the data is also proposed, which permits the prediction of gas holdup in structured packing with sufficient accuracy. 相似文献
15.
Marangoni效应对填料塔精馏传质过程的影响 总被引:4,自引:1,他引:4
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%。 相似文献
16.
受热降膜Marangoni效应临界状态表征 总被引:1,自引:0,他引:1
采用红外热成像技术,研究了水和Na2SO4水溶液受热降膜的Marangoni效应及对降膜流动的影响。发现在降膜的流向和径向都存在热Marangoni效应,但Marangoni数却不能较好地表征Marangoni效应对液膜流动的影响程度。因而引入Marangoni效应影响因子ε。结果表明,ε能较好地表征Marangoni效应对液膜流动的影响程度,且不同溶液受热降膜存在一个近似相同的临界值(εLc)。当εLεLc,降膜流向热Marangoni效应将引起降膜明显的扰动。根据εLc值,可获得临界Marangoni数MaTc,L。 相似文献
17.
采用计算流体力学(computational fluid dynamics,CFD)中的VOF方法对规整填料表面液相分布进行了三维建模和仿真,实现规整填料内液相分布的可视化并得到了液膜厚度和有效相界面积比等相关定量信息。通过分析比较不同物系的数值模拟结果,发现液体的表面张力和黏度都对填料表面上液体分布有影响。表面张力越小,液相在填料片上分布越均匀,有效相界面积比越大,液膜厚度越小;黏度增加,有效相界面积比和液膜厚度也随之增加。较之于黏度对液相分布的影响程度,表面张力的影响程度更大,为主要影响因素。本文还提出一个预测有效相界面积比的新公式,并将数值模拟结果与已有文献进行对比,吻合性较好。 相似文献
18.
The Marangoni effect induced by mass transfer at the interface between two immiscible liquids displays important influence on laboratory and industrial operation of solvent extraction. A systematic numerical study of the two-dimensional Marangoni effect in a two liquid layer system was conducted. The linear relationship of the inter- facial tension versus the solute concentration was incorporated into a mathematical model accounting for liquid flow and mass transfer in both phases. The typical cases analyzed by Sternling & Scriven (AIChE J., 1959) using the linear instability theory were simulated bv the finite difference method and good agreement between the theory and the numerical simulation was observed. The simulation suggests that the Marangoni convection needs certain time to develop sufficiently in strength and scale to enhance the interphase mass transfer, the Marangoni effect is dynamic and transient, and remains at some stabilized level as long as the mass transfer driving force is kept con- stant. When certain level of shear is imposed at the interface as in most cases of practical significance, the Maran- goni effect is suppressed slightly but progressively as the shear is increased gradually. The present two-dimensional simulation of the Marangoni effect provides some insight into the underlying mechanism and also the basis for further theoretical study of the three-dimensional Marangoni effect in the real world and in chemical engineering applications. 相似文献
19.
Matías Monsalvo 《Chemical engineering science》2007,62(23):6595-6603
In this work, the influence of structured packing on gas holdup in gas-liquid-solid dispersions has been studied. The experiments were carried out in an empty column and in column containing structured packing operating under identical conditions. Glass beads and silicon carbide particles were used as the solid material and the volumetric fraction of solids was varied from 0% to around 10%. The liquid viscosity was strongly modified using water, CMC solution and glycerol. The experimental results obtained with both columns were compared with previous results obtained in two-phase bubble columns. The influence of structured packing on the total gas holdup for different superficial gas velocities was found to be similar with and without suspended solids. Therefore, the results obtained in this work were analysed on the basis of correlations derived earlier for gas-liquid dispersions. Excepting the results obtained with glycerol, these correlations can predict the gas holdup of three-phase bubble columns with reasonable accuracy. 相似文献