Performance characteristics of a packing with boundary layer turbulizers Part 1. Pressure drop and loading point

A novel design of a honeycomb packing with turbulizers in the region of the boundary layer (Turbo-Pack) has been designed and investigated. The presence of turbulizers is shown to decrease the pressure drop per mass transfer unit in cases of both gas-film and liquid-film controlled mass transfer. A comparison of the best packings known so far from the literature shows that, regarding such an important parameter as pressure drop per mass transfer unit, the novel packing has significant advantages. On the basis of experimental data obtained by studying 11 different packing designs in liquids of various viscosity, equations for determining the performance characteristics of the novel packing are obtained. In the first part of this work, the data on packing design, pressure drop and loading point are presented.     

Performance characteristics of a packing with boundary layer turbulizers. IV. Gas-film controlled masstransfer

The gas-film controlled mass-transfer rate in a honeycomb packing, with stamped groove turbulizers (Turbo-Pack) which affect the region of the boundary layer, has been studied. An equation for determining the mass-transfer coefficient as a function of gas velocity and the geometrical dimensions of the packing has been derived. It is found that the effect of the height of packing blocks is far less than that forecast by Zhavoronkov's equation which was derived for packings with a much higher wall thickness. Comparison of experimental data relevant to the novel design with reference packings cited in the literature shows that as far as its low values of pressure drop per mass transfer unit are concerned the Turbo-Pack packing is superior to all other known packings.     

新型垂直板规整填料流体力学及传质性能

采用氧解吸实验,在直径190 mm的有机玻璃塔内,液相喷淋密度10～38 m³·m^-2·h^-1,F因子0.2～3.2 m·s^-1·（kg·m^-3）^0.5的实验条件下测定了一种新型垂直板规整填料的流体力学及传质性能。实验结果表明：垂直板填料的操作压降及传质性能均显著优于商业波纹填料。通过与几种经改进的250型波纹填料相比发现,两者泛点F因子整体上相当;在较高液体喷淋密度下,垂直板填料传质性能及压降均高于改进250型波纹填料;在低喷淋密度下,垂直板填料可实现压降低于改进250型波纹填料,而两者传质性能相当。此外,对填料结构改进对其性能的影响进行了单因素考察。     

Gas side controlled mass transfer in a new packing with stamped horizontal lamellae operating at extremely low liquid loads

The gas side controlled mass transfer coefficient of an easy to make packing, with stamped horizontal lamellae, designed for operating at extremely low liquid superficial velocity, between 0.04 and 1 m³/m² h is investigated. The absorption of SO₂ in sodium hydroxide water solution is used as a model process. Based on the obtained experimental data, an equation for calculating the gas side controlled mass transfer coefficient, with deviation of ±8% is presented.The comparison between the new packing and different highly effective packings shows that the new one has lower pressure drop at the same specific area and mass transfer coefficient, respectively higher mass transfer coefficient at the same pressure drop and specific surface.Of all compared highly effective packings, only the crossed strips packing, quite difficult to produce, has close, yet higher, pressure drop at similar specific surface area and volumetric mass transfer coefficient.     

液相流动方式对波纹规整填料性能的影响

根据液相在波纹规整填料片上呈现渗流、膜状流等不同的流动方式,选择5种不同的波纹规整填料对其流体力学和传质性能进行研究,以探究液相在波纹片上的流动方式对波纹规整填料性能的影响.研究结果表明,液相呈渗流流动的泡沫碳化硅波纹规整填料(SCFP型)有利于液体横向扩散和液膜均匀分布,当液相喷淋密度和气相F因子均较小时,其压降最低,传质效率最高;液相主要呈渗流流动、兼有膜状流动的双层错孔丝网填料(DMⅢ型)有利于波纹片两侧液体交换,强化液体在流动过程中的扰动,其压降及传质性能略逊于SCFP型填料;液相主要呈膜状流动的BX型、DMⅠ型及DMⅡ型填料波纹片表面液膜较厚,横向扩散能力差,其传质效率低于SCFP型和DMⅢ型填料.研究揭示了依靠渗流作用的波纹规整填料具有较好的应用性能,为波纹规整填料的进一步发展开拓了新思路.     

Mass transfer characteristics of liquid films flowing down a vertical wire in a counter current gas flow

The wetted-wire packing, mainly consisting of a bundle of vertical parallel wires, is a promising concept for the use in separation columns. To investigate the multiphase flow inside the packing in detail and to estimate the performance of the packing, experiments on liquid films on a single vertical wire in a counter current gas flow were carried out. To get information about the interfacial area, an optical measurement of the film thickness was carried out with a digital high speed camera and image recognition tools. By measuring the evaporation of water and aqueous polyvinylpyrrolidone solutions into air, the gas-side mass transfer was determined. The liquid-side mass transfer was examined by measuring the desorption of CO₂ from water into air. The results show that the mass transfer coefficients are comparable to those appearing in common structured packings. When assuming a sufficiently high wire packing density, a specific interfacial area similar to corrugated sheet structured packings can be reached. Previous studies predicted a low pressure drop per packing height and extended capacity limits compared to common packings. In consideration of these results, the wetted wire packing therefore is shown to be suitable especially for absorption processes where a low pressure drop is favourable.     

规整填料内置隔板边长对压降及传质的影响

传质发生在规整填料表面,通道内气体间相互碰撞形成的涡流在一定程度上强化传质,但消耗大量能量,压降升高。为减小压降,在每个传质单元中非波谷区加入隔板得到新型规整填料Mon-JKB-250Y。CFD（Computational Fluid Dynamics计算机流体力学）模拟发现,增大隔板边长,压降减小、气相总传质效率增大、单位压降下的传质系数先增大后减小,存在一个最适宜隔板边长。在F=1.2~2.7 m·s^-1·（kg·m^-3）^0.5范围内,隔板边长为14.7~16.8 mm时,单位压降下的传质系数达到最大。运用显色化学反应可视化技术验证CFD模拟结果,平均相对误差小于10%,CFD模拟结果可靠。     

Mass transfer coefficients for arranged packings with vertical walls under gas film control

Packings with vertical walls, especially structured packings, are distinguished by their high efficiency and low pressure drop per mass transfer unit. Yet for these types of packings there is still no universal relationship for calculating gas-film-controlled mass transfer coefficients. The present work proposes such an equation. For arranged and structured packings the new equation fits the experimental data, both new results and those taken from the literature, with a mean error of 9%.     

Towards the Development of Advanced Packing Design for Distillation in Rotating Packed Beds

The growing demand for flexible and compact separation technologies has promoted the application of high‐gravity technology, like rotating packed beds (RPBs). Mass transfer characterization and packing design play an important role in the development of this technology. This article provides a systematic approach towards the evaluation of packing and the development of advanced packing design for distillation in RPBs. For the latter, an additive manufacturing approach is used to develop a new Zickzack packing for RPBs. The new packing provides better mass transfer at reduced pressure drop compared to available conventional packings, while being competitive in terms of mass transfer with the industrially applied rotating zigzag bed at significantly reduced pressure drop.     

翅片导流板填料应用于旋转填料床的特性

For an alcohol/water system and with fin baffle packing, continuous distillation experiments were carried out in a rotating packed bed (RPB) system at atmospheric pressure. The effects of the average high gravity factor (β), liquid reflux ratio (R) and feedstock flux (F) on the momentum transfer and mass transfer were investigated. The gas phase pressure drop of RPB increased with the average high gravity factor, liquid reflux ratio and feedstock flux, which was 13.55-64.37 Pa at β of 2.01-51.49, R of 1.0-2.5, and F of 8-24 L&;#8226;h－1 for a theoretical tray in the RPB with fin baffle packing. The investigation on the mass transfer in the RPB with different packings showed that the number of transfer units of RPB with a packing also increased with the average high gravity factor, reflux ratio and feedstock flux. It is found that the fin baffle packing (packing III) presents the best mass transfer performance and lowest pressure drop for the height equivalent to a theoretical plate (HETP), which is 6.59-9.84 mm.     

Application of modern packings in thermal separation processes

A report is presented on the performance of modern dumped and structured packings for application in the field of thermal separation processes. The evaluation of the results is based on extensive experimental investigations of rectification, absorption, and desorption systems. The following are indicated: the efficiency in terms of the number of theoretical stages per unit height or in terms of the height of transfer unit or volumetric mass transfer coefficient, the pressure drop per unit height as well as per theoretical stage or per gas phase transfer unit, and the liquid hold-up, whereby either the gas capacity factor or the liquid load was adopted as influencing parameter, and finally the maximum gas capacity factor as a function of the flow parameter. The results are presented in diagrams and tables.     

复合板网填料性能研究

对一种新型的金属复合板网填料进行了研究,它是由三层板网贴合为复合基材后加工成波纹填料。在500冷模实验塔内对250Y型填料的测试结果表明复合板网填料具有显著的性能优势。三层复合板网填料的压降比常用的金属板波纹填料低60%以上,通量大20%～40%。氧解吸实验结果表明三层复合板网填料的分离效率明显高于单层板网填料,尤其在液气比低的工况下,效率可以倍增,和广泛应用的金属Mellapac填料相比,复合板网填料的分离效率能高30%左右。     

Füllkörper oder Packungen? Wem gehört die Zukunft?

Over the years a large number of dumped and ordered packings have been developed for effective treatment of material in absorption, desorption, extraction and rectification columns. The task of these column packings is to improve the mass transfer between a liquid phase and a gas or vapor phase. Furthermore, they also have to assure large throughputs at low pressure drops. When elaborating possible solutions for the separation of liquid mixtures or for cleaning flows of waste air or waste water in mass transfer columns, the planning engineer repeatedly faces the question of which dumped packing or which arranged packing presents the most favorable design from a process engineering standpoint. In recent years the opinion has often been voiced that arranged packings are always more effective than dumped packings. The purpose of this paper is to show that a number of applications exist in which modern dumped packings are equal or even superior to arranged packings. On the basis of selected examples the author discusses when the use of a structured packing is preferable with regard to process engineering.     

QH-1型扁环填料用于高液气比操作时的性能研究

在内径186mm有机玻璃塔中 ,对16和2 5QH 1型扁环填料的流体力学和传质性能进行了研究 ,得出了计算其压降、液泛气速、泛点填料因子、湿填料因子和液相总传质单元高度的关联式。并与16鲍尔环填料进行比较 ,结果表明 ,QH 1具有优良的流体力学和传质特性。     

PERFORMANCE OF A WETTED-WALL SHEET BUNDLE COLUMN

The performance of a wetted-wall sheet bundle column with vertically aligned sheets placed inside as liquid film supports was investigated as an alternative to a wetted-wall fiber bundle column used for gas and liquid contacting. It avoids or simplifies some of the design problems associated with using fibers and still retains the advantages possessed by the fibers such as low pressure drop and high mass transfer coefficient. A comparison with the conventional Raschig ring packings and stainless steel tube bundles show that the fibers and sheets which were made of light weight material has definite advantages in reducing the weight and cost of the packing material in the column substantially     

Characterization of New Wire Gauze-Structured Packing: Experimental Study

Structured packings are usually employed for increasing the surface contact between vapor and liquid in the absorber and distillation of columns. Experimental investigations are performed to present a high-capacity new wire gauze-structured packing, namely, PACK-1300XY, which is the combination of PACK-1300X and PACK-1300Y. The new PACK-1300XY shows improved efficiency of separation and pressure drop. Comprehensive parametric investigations are carried out to calculate the efficiency of mass transfer and the wet/dry pressure drops under different operating conditions. The new wire gauze-structured packing reduces wet and dry pressure drops by more than 10 % in comparison to PACK-1300Y. In addition, PACK-1300XY decreases the height equivalent to a theoretical plate by more than 5 % compared to PACK-1300X.     

Comparative study of dry pressure drop and flow behaviour of gas flow through sieve plate packing

Sieve plate packing is a newly developed packing that has been used in several industries due to its simple structure and operating flexibility, and no liquid flooding. In this work, first, systematic experiments were conducted to measure the pressure drop of gas flow through six sieve plate packings. The results indicated that the geometric characteristics of the packing have complicated effects on the pressure drops. Based on this, CFD simulations on the gas flow field were conducted using the realizable k-ε model, and flow behaviours such as the pressure drop, pressure nephogram, and velocity distributions within different packings were obtained. The simulation results clearly showed interesting flow patterns, including the contraction and expansion of the gas stream through the sieve hole, the flow separation on the sharp edge of the hole, and the vortexes formed when gas impacts the downstream plate. By comparing the flow patterns and the pressure drop under different packings operating at different conditions, the effects of the geometric characteristics of the packing on the pressure drop could be clearly distinguished from the flow behaviours, so that the variations in pressure drop with various packing structures were clearly indicated. Finally, based on the experimental data and the simulated results, correlations for the prediction of the pressure drops were proposed. This work will provide a useful basis for understanding the flow behaviour of gas and liquid two-phase flow in sieve plate packing.     

孔板波纹填料的结构参数对其性能的影响

在内径Φ30 0mm的填料塔中研究了孔板波纹填料的结构参数对液相轴向混合特性、流体力学和传质性能的影响 .研究结果表明 ,轴向返混参数随开孔率、倾角的增加及盘高的减小而增加 ,填料层压降随开孔率、盘高的增加及倾角的减小而降低 ,传质单元高度随倾角的增加、盘高的减小而降低 ,开孔率对传质单元高度的影响有一个适宜值 .通过对实验数据的回归分析得出了轴向返混参数、填料层压降及传质单元高度的关联式 .该研究结果对孔板波纹填料的开发与设计具有参考价值     

气液两相并流下行通过堆叠筛板填料的压降特性

堆叠筛板填料已在核电站放射性气体除气塔中得到成功应用。针对这一新型填料的应用设计,在较广泛的气液流量下,对气液并流下行通过不同规格堆叠筛板填料的阻力特性进行了系统的实验。实验填料共6种规格,孔径参数包括6、10和14 mm,不同孔径填料对应不同的孔间距、板间距,每种孔径填料具有正方形和正三角形两种筛孔分布方式。通过压降数据分析,研究了流动参数和几何参数（孔径、开孔率、布孔方式、板间距）对气液两相并流通过填料的流动行为及压降特性的影响;结合多孔板阻力系数经验公式提出了堆叠筛板填料干板阻力系数的计算模型,模型很好地反映了不同几何参数对干板阻力系数的影响,预测偏差在5%范围以内;基于均相流模型提出了堆叠筛板填料气液两相压降的预测模型,模型预测偏差在10%范围以内。研究工作对堆叠筛板填料塔的应用设计及进一步的传质动力学研究有一定参考价值。     

新一代的乱堆填料——梅花扁环

The hydrodynamics and mass transfer of Plum Flower Mini Ring(PFMR),Pall Ring and Intalox Saddle were studied in a 600mm diameter column with air-oxygen-water system over a wide range of liquid loasds.It was shown from the experiments that PFMR had much lower resistance,larger throughput and higher mass transfer efficiency than Pall Ring and Intalox Saddle.It was clear from the comparison that existing equations could not predict the performance of packings very well at high liquied loads.Therefore,new semi-empirical equations of pressure drop,flooding gas velocity and height of transfer unit(HTU)were proposed based on the experimental data.