Einfluss ausgewählter Medienstrukturparameter auf das Betriebsverhalten von Ölnebelfiltern

The relevant mechanisms in oil mist filtration and their impact on operational behavior of the filters have received increasing attention in research over the last few years and are qualitatively well understood by now. However, so far the relationship between structural properties of the filter media and the operational behavior of the filters is relatively unknown. For the identification of filtration‐relevant structural parameters, textile properties of different filter media were characterized with various methods. The operational behavior of the characterized filter media was then examined and compared.     

Druckstoßabreinigung textiler und starrer Filtermedien: Abreinigungsrelevante Parameter

Pulse Cleaning of Textile and Rigid Filter Media – Characteristic Parameters To characterize the pulse cleaning of textile and rigid filter media in technical filter houses and test rigs, by now mainly tank pressure and valve opening time have been used as characteristic parameters which are however dependent on the whole geometry of the plant and which therefore do not allow a comparison between different technical systems. Thus, the question is raised which parameters of a cleaning pulse are decisive for its performance. By knowing these parameters, an experimental setup could be adjusted in a way that it shows the same cleaning behavior like a filter house, so that the laboratory filter tests are comparable to technical filter cycles. On a filter test rig which can be used for both textile and rigid filter media as well as on a pilot plant designed for Herding alpha filter candles, experiments concerning the influence of these different parameters on the cleaning behavior were performed. The characteristic figures maximum pressure, pressure integral, and pressure rise velocity of each pressure pulse were determined and compared with the cleaning efficiency achieved. As result of comprehensive regression analyses we found that especially the maximum pressure and the pressure rise velocity during zero‐passage of a cleaning pulse are decisive for the cleaning result. The practical conclusion is that pulse jet systems should be optimized with regard to these parameters.     

Pulse Jet Cleaning of Textile and Rigid Filter Media – Characteristic Parameters

To characterize the pulse cleaning of textile and rigid filter media in technical filter houses and test rigs, by now mainly tank pressure and valve opening time have been used as characteristic parameters. The pressure pulse formed, however, depends on the whole geometry of the plant so that these operation parameters do not allow a comparison between different technical systems. Thus, the question is raised – also for the development of new pulse jet systems – which parameters of a cleaning pulse are decisive for its performance. By knowing these parameters, an experimental setup could be adjusted in a way that it shows the same cleaning behavior like a filter house so that the laboratory filter tests are comparable to technical filter cycles. On a filter test rig which can be used for both textile and rigid filter media as well as on a pilot plant designed for Herding alpha filter candles, experiments concerning the influence of these different parameters on the cleaning behavior were performed. By inserting different orifices into the blow tube and varying the tank pressure and valve opening time, cleaning pulses of great variability were generated and the history of pressure drop over the filter medium or with candles even on the filter surface was recorded. The performance parameters maximum pressure pressure integral and pressure rise velocity of each pressure pulse were determined and compared with the cleaning efficiency achieved. As result of comprehensive regression analyses we found that especially the maximum pressure and the pressure rise velocity during the zero passage of a cleaning pulse are decisive for the cleaning result. The practical conclusion is that pulse jet systems should be optimized with regard to these parameters. The pressure integral however is not a significant performance parameter.     

分离细小颗粒的真空带滤机用滤布的特性及发展

本文将述及在真空过滤机的实际应用中的细微颗粒的分离趋势和带滤机用滤布的要求,并着重讨论多层滤布在不同行业中越来越广泛应用的可能性。     

Status and prospects for development of polyester fibre and yarn production technology

Current production schemes for polyester fibres and textile and industrial yarn and the prospects for development of their production technology are examined. Changing to economical direct melt spinning processes and to use highly efficient units for separate and combined spinning-drawing of fibres and yarn spun from melt and granulate, increasing textile fibre spinning and texturing speeds, and introducing continuous process and product quality control systems are the main trends in the evolution of modern plants. Most of the attention is being focused on creating flexible process lines that make it possible to raise the quality, rapidly change the assortment, and manufacture products that satisfy market requirements. __________ Translated from Khimicheskie Volokna, No. 4, pp. 28–39, July–August, 2006.     

Have Abrasive Liquid Filtration Applications Met their Match with TufTex Filter Media?

In many industrial liquid filtration applications filter media can be subjected to a severe abrasive loading that can limit their operating lifetime, and therefore result in increased plant downtime and reduced process efficiency. Madison Filter Ltd, UK, has developed a solution to such abrasion problems. Tuf-Tex^™ is a patented treatment that can be applied to standard textile based filter media to increase abrasion resistance. Professor Richard Lydon, Richard Allan & Joseph Johnson discuss the treatment technology and present both laboratory and field performance data.     

Standards for the fire hazard of clothing: The Australian experience

The Australian Children's Nightwear Standards have been accepted as the basis of legislation in all States of Australia and by the Commonwealth Government. The standards are based on the philosophy that garment design as well as combustion characteristics of the material is an important consideration in assessing the fire hazard of nightwear. Using this approach a classification system has been devised which place children's nightwear into three categories of potential fire hazard. If a garment cannot be classified then it cannot be legally sold in Australia. The combustion characteristics tested are ease of ignition, rate of flame propagation and surface burn properties. For classification all materials used for children's nightwear must pass the latter test. The design of the standard test methods, criteria for classification and the concepts of safe design were developed by collection data from burns accidents and burnt clothing from accident victims from the burns research unit of a large children's hospital and by the study of the burning behavior of clothing on a manikin. The combustion criteria are not so stringent as to require the use of inherently flame resist materials or the use of flame retardant finishes. This approach in combination with safe design criterial enable commercially available textiles to meet the legislative requirements for children's nightwear. This mean that the nightwear standards are inexpensive to attain and do not require a sophisticated textile technology. A consumer labeling system has been designed to describe the three categories but yet there is no evidence to suggest that this had had any effect in reducing the number of burns accidents—consumers apparently regrading safe nightwear as a low priority. An inconsistent aspect of the calssification system is the incorporation into the standards in 1977 of criteria to prevent the classification of cotton flannelette nightdresses and the incorporation of arbitrary requirements for other nightdress containing cotton. These inconsistencies have been caused fundamentally by a problem which continues to bedevil the writing of good standards in Australia—that is, the lack of nationwide statistics on burns accidents.     

Air filter media functionalized with β-Cyclodextrin for efficient adsorption of volatile organic compounds

Respiratory air filter media invariably comprise a nonwoven textile fabric. The limitation of the existing fibrous air filter medium is negligible protection against hazardous volatile organic compounds (VOCs). In this study, the filter media was cross-linked with β-Cyclodextrin for the surface functionalization. The VOC adsorption performance of the functional fabric was explored for styrene, benzene, and formaldehyde and also compared with a commercial nonwoven face mask. The functionalized fabric performed much better than commercial masks with adsorption capabilities of 18.80 μg mg⁻¹ (for xylene), 14.75 μg mg⁻¹ (for benzene), and 0.06 μg mg⁻¹ (for formaldehyde). Further, the cross-linking did not affect the air permeability (204 cm³ cm⁻² s⁻¹) thus showing no resistance to breathing. β-Cyclodextrin functionalized textiles can be promising respiratory air filter media having the potential to capture a variety of VOCs yet remain breathable.     

Mastering the shade…a CAD system for colour

Since the introduction of computer-aided design technology into the textile industry, imprecise on-screen colour has become a recognised weak link in the production chain. Colour mismatch between the different media has led to costly modifications, as well as reaffirming many a designer's technophobia. However, a new system has been developed which is user-friendly, versatile and which communicates colour accurately.     

Theoretical Modeling of Filtration by Nonuniform Fibrous Filters

Modeling commercial filter media using classical theories results in incorrect filter pressure drop and efficiencies and this is attributed to media inhomogeneity. The use of an arbitrary inhomogeneity factor is seen to be inadequate in accounting for the effect of operating conditions on the performance of inhomogeneous filter media. A simplistic theoretical modeling approach is described here to account for the variations in filter packing densities and to estimate their effect on the media particle capture characteristics. The theoretical modeling results are used in obtaining an equivalent filter packing density distribution from media local efficiency measurements. Considering this variation in the theoretical models is seen to result in better prediction of media performance over a wide range of operating conditions. The observed deviation of experimental efficiencies from the theory at smaller Peclet numbers can be explained from the results of the theoretical analysis.     

Fibre identification and the quantitative analysis of fibre blends

The fibre composition of a textile is a fundamental characteristic in determining the product's behaviour, end use and value. This paper reviews recent developments in the fields of fibre identification and blend analysis, several of which are extensions of more traditional methods. Difficulties and advantages associated with the techniques described are considered.     

Loading of fibrous filter media and newly designed filter configurations by salt particles: An experimental study

Various fibrous filter media, including surface filter media, depth filter media, woven and nonwoven filter media, were tested and particle loading capacity was calculated using bench‐scale setup via a new estimation approach which was proposed and experimentally verified with Novick‐Kozeny model. Multi‐element structured arrays (MESAs) developed by our research group were evaluated as well for particle loading capacity and filter lifetime on 24″ × 24″ full scale test rig (based on ASHRAE 52.2 Standard). Effects of varying filter media type, filter depth, pleat count and MESAs' element count on salt particle loading performance were experimentally investigated. The experimental studies showed that nonwoven activated carbon fiber filter media have allowed significantly higher salt particle loading capacity and longer useful lifetime compared to woven or nanofiber entrapped media. Furthermore, MESAs were able to significantly enhance loading capacity for salt particles and useful lifetime due to higher filtration area and lower filtration velocity. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3739–3750, 2016     

陶瓷过滤管管壁内气体流动的LBM并行模拟

采用格子Boltzmann方法,编制并行程序,计算了陶瓷过滤管管壁内的流体流动,从微观角度对滤管多孔介质结构内的流动进行分析。以陶瓷过滤管管壁扫描电镜图片为基础,根据实际滤管的厚度,确定计算中的多孔介质结构。分析了无膜滤管微细通道内的速度及压力随入口参数的变化情况以及多孔介质结构对速度的影响,给出了压力沿滤管厚度方向的变化曲线;分析了有膜滤管内的流动情况,给出了压力变化曲线,由计算结果可知,滤膜压降占滤管压降的比例较大。对过滤管微孔结构内流动的研究,可为陶瓷过滤管的性能优化提供理论指导。     

Design and Optimization of Fibrous Filter Media Using Lifetime Multipass Simulations

The goal of this study was to optimize fibrous filter media by increasing the dust holding capacity (DHC) while maintaining the β ratio and initial pressure drop of the filter media. The key was the use of microstructure models to optimize the filter media. The microstructure of three different variations of a filter media for oil filtration was modeled by using the FiberGeo module of the GeoDict® software package. It was found that by optimizing the fiber volume distribution over the height of the filter media, higher DHC values could be achieved while keeping the pressure drop considerably low. This confirms the hypothesis that the macroscopic properties of the filter element can be improved by modifying the microstructure of the filter media.     

Drag Correlation of Drop Motion on Fibers

The objective of this article is to correlate a drag coefficient to the Reynolds number for axial motion of barrel drops on fibers. This work includes effects of vibration-induced motion of droplets and coalescence. The study of motion of drops is important to understand the drainage behavior of droplets. Drainage of liquid helps to eliminate moisture from media samples before applying thermal energy and hence reducing the drying cost. A significant amount of literature describes the mechanisms of droplet capture, coalescence, and drainage from filter media and models are developed at a scale that accounts for the liquid held in the filter through averaged parameters such as saturation. Few papers discuss the motion of individual drops attached to fibers.

The study of drop motion on fibers is of scientific and economic interest for many possible applications like printing, coatings, drug delivery and release, and filters to remove or neutralize harmful chemicals or particulates from air streams. Gas convection–induced drop motion in fibrous materials occurs in coalescing filters, clothes dryers, textile manufacturing, convection ovens, and dewatering of filter cakes. Droplet removal can significantly reduce drying costs by reducing the free moisture contained in fibrous materials prior to applying thermal drying techniques.

In this article, the experimental drag coefficient versus Reynolds number data are compared for 1-D and 3-D cylindrical drop models. The results show that 1-D models are inadequate to predict the drag coefficient but do show the same general trends.     

玻纤复合滤料的特性及应用

介绍了玻璃纤维与高性能合成纤维的优缺点。根据实际应用领域环境特点和要求,用合理的纤维配比制造复合过滤材料,通过对其制作过程、技术要求、主要产品特性以及在具有代表性行业领域中应用的介绍,为生产和选用提供有益的借鉴与参考。     

Textile Waste Waters: Treatment and Environmental Effects

The paper considers the use of water and chemicals in the textile industry and the volume, nature and composition of process effluents, the effect they have on the environment and the limitations they pose on the reuse of water. An outline is given of the methods available for treatment of waste waters from the industry, on site or at a Water Authority's works and the effects that chemical constituents of the effluents have on the treatment processes and on disposal of water and sludge. The assessment and significance of biodegradability and the extent of present-day knowledge on the biodegradability of the main classes of chemicals used in textile processing are discussed. The paper concludes with a section dealing with the removal of colour from waste waters.     

Figure of Merit of Composite Filters with Micrometer and Nanometer Fibers

We investigate the filtration performance of composite filters composed of micrometer and nanometer fibers. The filter quality is evaluated using the figure of merit, also known as the quality factor. We use analytical expressions for the pressure drop and filtration efficiency to compute the figure of merit. The effects on the figure of merit by fiber diameter, solidity, and thickness of nanometer and micrometer fibers and face velocity are investigated. Experimental data obtained using conventional filter media and nanofiber composite filters are then used to verify the calculated results. We find that for large particles (approximately 0.1 μm and above), nanofibers can improve the figure of merit compared to conventional filters. Smaller fiber size, larger solidity, and thickness of the nanofiber layer lead to better filtration performance in this size range. For small particles (approximately below 0.1 μm), nanofibers do not improve the figure of merit compared to conventional filter media. Larger fiber size, smaller solidity, and thickness of the nanofiber layer are preferred in this size range. We demonstrate that our procedure using analytical expression is a fast and effective tool for filter media design.     

玻纤覆膜滤料在水泥熟料生产线中的应用

介绍了福泰(Filtex)覆膜滤料在4500t/d带纯低温余热发电水泥熟料生产线中的应用与维护。通过对覆膜滤料使用情况的跟踪与数据分析和定期抽换检测,及时了解滤料在该项目上的积灰程度、是否结露、强度损失等工作情况,对个别破袋现象和结露现象进行及时的处理并总结了维护经验。     

曝气生物滤池-臭氧氧化-曝气生物滤池组合工艺对印染废水的深度处理

采用曝气生物滤池(BAF)-臭氧氧化-曝气生物滤池三段组合工艺对二级生化后的印染废水进行深度处理,进水COD为90～150 mg/L,色度为16-32倍,经该工艺处理后的出水COD<35 mg/L,去除率>75%,色度降到4倍以下.工程运行实践表明,该深度处理系统运行稳定,处理效率高,出水水质达到印染场洗水工序对水质的要求.