玻纤滤材过滤阻力的预测

过滤阻力和过滤效率是玻纤空气滤材的关键参数。实际应用中,为了优化滤材阻力和效率之间的矛盾,通常会选择多种尺寸的纤维搭配使用。对这种滤材的过滤阻力进行预测,对于高性能滤材的研制具有重要意义,而目前对玻纤滤材过滤阻力的理论计算大部分还局限于单种纤维的理想情况。本文将针对由多种玻纤原料制备的滤材,根据不同玻纤的比表面积,利用Kozeny-Carman方程计算由此制备的滤材过滤阻力。这种方法计算的过滤阻力理论值与实际测量值非常接近,相关系数R2=0.996 9,可为过滤材料的优化设计提供一定的依据。     

超薄ePTFE纳米纤维膜用于PM2.5的高效治理

针对中高浓度PM2.5的高效过滤问题,选取颗粒粒径与膜孔径比值(dP/dm)范围为0.86~4.46,厚度小于等于1 μm的三种不同结构的超薄ePTFE纳米纤维膜展开应用性能研究。考察了过滤速度、PM2.5浓度和膜结构对过滤性能的影响以及膜的再生性能。得益于纳米纤维堆叠的网状结构,在过滤速度为1.2~4.8 m/min,进口浓度为200~1000 mg/m3的范围内,三种超薄ePTFE纳米纤维膜均能实现PM2.5的高效截留(>99.5%),其稳定压降和压降增长速度均随过滤风速和进口PM2.5浓度增加而增加,但初始压降和出口浓度仅随过滤风速增加而增加,与进口浓度关系不大。超薄ePTFE纳米纤维膜层数少、过滤阻力低(≤130 Pa)且膜表面光滑(表面粗糙度小于1 μm),降低了滤饼与膜表面附着力,使滤饼易于脱落,在4次循环实验中展现出良好的再生性能。横向对比结果显示,dP/dm为0.86,膜厚度为0.5 μm的超薄ePTFE纳米纤维膜兼具最低的过滤压降(30 Pa)、良好的过滤效率(99.93%)及再生性能好的优势,在中高浓度PM2.5空气净化领域表现出较好的应用前景。     

高温高效玻璃纤维针刺毡滤材特性及其应用

本文介绍了研制应用玻璃纤维针刺毡滤材的重要意义。玻纤针刺毡滤材，不仅具有绢物玻纤滤布耐高温、耐腐蚀、尺寸稳定、伸长率小、强度高的优点。由于毡层纤维呈单纤维三向微孔结构，因此空隙率高，对气体的过滤阻力小，过滤速度快，除尘效率高，从而使除尘器占地面积小、设备投资小、运行动力消耗省、同时突破了以往玻纤织物滤布不能应用于高气布比的脉冲袋滤器的禁区。文中通过大量的应用实例，说明使用玻纤针刺毡滤材，将给用户带     

静电纺纳米纤维复合梯度型空气过滤材料的研究进展

概述了静电纺纳米纤维及其复合梯度过滤材料的特性,详述了国内静电纺纳米纤维复合梯度型空气过滤材料的制备、过滤模型理论及数值模拟等研究进展。基于不同纤维层过滤不同粗细颗粒物,每一层纤维网发挥各自独特作用,可采用多种结构和折叠结构复合,增大过滤面积,制备多层梯度的静电纺纳米纤维复合滤材,使滤材具有高效低阻、容尘量大、使用寿命长等特点,是未来空气滤材的重点研发方向;同时应加强过滤模型设计与数值模拟研究,通过滤材的应用数据不断修正模型,促进滤材性能的改进。     

高温高效玻璃纤维针刺毡滤材的特性及其应用

本文介绍了研制应用玻璃纤维针刺毡滤材的重要意义.玻纤针刺毡滤材,不仅具有织物玻纤滤布耐高温、耐腐蚀、尺寸稳定、伸长率小、强度高的优点.由于毡层纤维呈单纤维三向微孔结构,因此空隙率高,对气体的过滤阻力小,过滤速度快,除尘效率高,从而使除尘器占地面积小、设备投资少、运行动力消耗省、同时突破了以往玻纤织物滤布不能应用于高气布比的脉冲袋滤器的禁区.文中通过大量的应用实例,说明使用玻纤针刺毡滤材,将给用户带来较大的经济效益、环保效益和社会效益.     

超疏水超亲油玻璃纤维过滤膜的制备及其乳化水分离效率

通过溶胶-凝胶法,以MTES(甲基三乙氧基硅烷)为前驱体,在玻璃纤维(玻纤)过滤膜表面直接进行水解缩合反应,制备具有高效油水分离功能的玻纤过滤膜材料。通过扫描电子显微镜和红外光谱分析MTES处理前后玻纤过滤膜的微观形貌与表面组成的变化,并通过接触角仪测试玻纤过滤膜的接触角,采用Karl Fischer水分仪测试玻纤过滤膜的油水分离效率。结果表明:经过MTES处理后,玻纤过滤膜的微观孔隙结构不变,而纤维表面布满疏水亲油的–CH3基团和纳米凸起结构,处理后的玻纤过滤膜有超疏水超亲油性能,玻纤过滤膜对乳化水的油水分离效率可以达到96.09%。     

静电纺丝复合滤材制备及性能研究

研究了纺丝液浓度对聚丙烯腈(PAN)静电纺丝纤维直径,以及对PAN静电纺丝纳米纤维膜复合滤材过滤性能的影响。测试结果表明,纺丝液浓度增加,静电纺丝纤维直径变粗,孔径增大,其中质量分数为16%的纺丝液具有良好的纺丝性能,静电纺丝所得的纳米纤维直径均匀,复合后滤材在颗粒直径0.3μm,过滤风速5.3 cm/s的测试条件下,过滤效率达到99.98%,阻力为138 Pa,达到H13级别,具有高效低阻特性。     

陶瓷纤维过滤材料的制备和性能

为制备一种低阻力、较高机械强度和耐一定温度的刚性过滤材料,分别将剪短的氧化铝纤维、硅酸铝纤维和高铝纤维通过机械搅拌均匀分散在水玻璃中制成浆料,然后真空吸滤成形、烘干、高温烧成过滤材料,测试三种滤材的过滤阻力和抗弯强度后发现,氧化铝纤维和高铝纤维滤材的性能较好。把氧化铝纤维和高铝纤维按不同比例混合,以相同的工艺制备过滤材料,通过对滤材的性能分析,确定当氧化铝纤维和高铝纤维的比例为9∶1,800℃烧成,可得到过滤阻力为41Pa/m/min,抗弯强度为6.9MPa,孔隙率为78%的过滤材料。     

PTFE纤维制备技术的研究进展

介绍了聚四氟乙烯(PTFE)纤维的结构和物理化学性能;详述了PTFE纤维制备技术,如载体纺丝(湿法纺丝、干法纺丝)、糊料挤出纺丝、熔体纺丝、切割膜裂法等纺丝工艺,比较了各种纺丝工艺的优缺点,载体纺丝法制备PTFE纤维技术较为成熟,可制备线密度较小的纤维;叙述了PTFE纤维在过滤材料、医学材料、密封填料和纺织工业等方面的应用;指出我国PTFE纤维发展的关键是改进及开发新的制备技术,提高PTFE纤维的质量及产量。     

多级结构静电纺纳米纤维膜在空气过滤领域研究进展

静电纺纳米纤维膜具有纤维直径小、比表面积大、孔隙率高等优势,使其在空气过滤领域具有广阔的应用前景。相比特殊结构的纳米纤维膜,常规的静电纺纤维膜堆积密度大、过滤阻力高,增加了在实际使用中的能源消耗。从静电纺纤维膜结构和过滤性能的角度探讨了高效低阻空气过滤纳米纤维膜的构筑,介绍了珠粒、突起和多孔结构纤维膜在空气过滤领域的研究进展,指出了多级结构静电纺纳米纤维膜是高效低阻空气过滤膜的重点研究方向。     

厚度对玻纤滤纸过滤性能的影响

通过实验测量过滤纸厚度、过滤效率和阻力,最终确定厚度与过滤性能(a值)的关系。通过实验测试的3种真空度下的滤纸厚度、过滤效率、阻力、a值的数据表明:真空度越小的滤纸,厚度越厚越蓬松,相应的过滤性能a值也越高。     

疏油改性对玻纤聚结元件气液过滤性能的影响

气液聚结元件在压缩气体净化等工业领域应用广泛,目前聚结元件的性能难以满足行业不断增长的需求,但是提高聚结元件过滤效率的同时,阻力也会随之升高,不利于其综合性能的优化。为研制低阻高效的聚结元件,利用不同浓度氟硅氧烷丙烯酸酯溶液对聚结滤材进行疏油改性,分析了表面能不同的滤材在气液过滤过程中压降、过滤效率以及二次夹带现象的变化,并对改性在聚结滤芯上的应用效果进行研究。结果表明,改性滤材在过滤效率提高10%的同时,稳态压降可降低约30%。滤材表面性质变化导致的跳跃压降减小是稳态压降降低的主要原因;滤材内液体分布对扩散、惯性分离作用的增强以及二次夹带的减少是效率提高的主要原因。对于表面能不同的疏油滤材,稳态压降和效率均随表面能的减小而升高。聚结滤芯经过改性后品质因子最大可提高92%。     

Influence of oleophobic modification on gas-liquid filtration performance of glass fiber coalescing elements

Gas-liquid coalescing elements are widely used in industrial fields such as compressed gas purification. Currently, the performance of coalescing elements is difficult to meet the growing needs of the industry. However, while increasing the filtration efficiency of the coalescing element, the resistance will increase simultaneously, which is not conducive to the optimization of the comprehensive performance. To develop low-resistance high-efficiency coalescing elements, the coalescing filter materials are modified by different concentrations of fluorosilicone acrylate solution. The evolution of pressure drop, filtration efficiency and secondary entrainment of the filter materials with different surface energy during the gas-liquid filtration process were analyzed, the modified filter materials were fabricated into coalescing filters for verification. The results showed that, the filtration efficiency of the modified filter materials was increased by approximately 10%, and the steady-state pressure drop was reduced by approximately 30%. The decrease in jump pressure drop caused by changes in the surface properties of the filter materials is the main cause of the decrease in steady-state pressure drop. The increase in filtration efficiency is caused by the enhancement of diffusion and inertial separation, and the reduction of secondary entrainment. For oleophobic filter materials with different surface energy, the pressure drop and filtration efficiency increase with the decrease of surface energy. The quality factor of the coalescing filter element can be increased by up to 92% after modification.     

聚结层排布对高压天然气净化用滤芯过滤性能影响的实验研究

本工作利用聚结滤芯过滤性能实验装置,通过改变滤芯内部的滤材排布,研究了聚结层为单一滤材以及由不同滤材排布组合的滤芯过滤性能,分析了聚结层排布方式对过滤效率、压降、饱和度及液体分布的影响。结果表明,由单一滤材组成的滤芯过滤效率随滤材孔径减小而增大,但孔径最小时由于压降较高,导致滤芯综合过滤性能反而最差。疏油在前、亲油在后的聚结层排布方式可提高滤芯过滤效率、减少液滴二次夹带,且以两层相同滤材交错排列的滤芯过滤效率比单层滤材交错排列明显更高,压降也相对较低,使得综合过滤性能显著提升。继续增加进气侧的疏油滤材层数可延缓压降增长、提高运行寿命,滤芯稳态品质因子达到最大值(0.30 kPa-1)。聚结层排布方式对滤芯过滤性能的影响主要通过改变液体分布形式而实现,且末层滤材的通道结构变化是导致不同聚结层排布方式的滤芯过滤性能出现差异的主要原因。     

反吹风玻璃纤维覆膜滤料的研制及应用

通过对膨体过滤布、滤布表面处理技术、ePTFE膜以及覆膜工艺的研究,研制出过滤效率高、运行阻力低的反吹风玻璃纤维覆膜滤料,并对该种滤料的应用进行了实例举证,例证表明反吹风覆膜滤料清灰效果好,使用的反吹风强度较低,大大延长了滤料的使用寿命,降低了产品的运行费用.     

Effects of Surface Finish of Nonwoven Fabric Bag Filters on Filter Efficiency

The effects of the surface finish of the bag filter for industrial use on the spatial distributions of the fiber mass, air permeability, and thickness were examined using a nonwoven fabric filter made of polytetrafluoroethylene (PTFE) with no surface finish and two nonwoven fabric filters made of PTFE with different surface finishes, i.e., resin finish and membrane finish. The surface finish had no impact on the non-uniformity in air permeability distribution. However, the air permeability of the filters was reduced with the use of a surface finish. In addition, the specific filtration resistance of the filter media increased by approximately 1.2 times in the case of the resin finish and 4.2 times for the membrane finish. Hence, the influence of the membrane finish on the filter efficiency is extremely strong.     

Effect of Support Material Properties on Dynamic Membrane Filtration Performance

A dynamic membrane is defined as a cake layer which forms on a support material, for example, filter cloth or mesh when the liquid to be filtered includes suspended particles. Formation of an effective dynamic cake layer is highly related with the retention of particles on the support material surface. Therefore, support material properties are considered to be of prime importance in the performance of dynamic membrane treatment systems. This study investigates the effect of support material properties including pore size and structure of the material on dynamic membrane formation and performance. In this concept, a comparative evaluation was made between support materials which have different yarn types. The results showed that high total suspended solids removal efficiency (>98%) could be achieved by using dynamic membrane filtration technology. Mono-monofilament and staple filter cloths were determined as the most appropriate materials in terms of the critical fluxes which were 9.2 L/m² · h and 17–19 L/m² · h for mono-mono filament and staple materials, respectively. However, considering the results of more long-term experiments, mono-monofilament filter cloth was found more suitable for cake layer accumulation. Therefore, we postulate that mono-monofilament cloth can be used in dynamic membrane filtration systems as an alternative to traditional membranes in anaerobic membrane bioreactors.     

A study on the effects of laminating temperature on the polymeric nanofiber web

The use of fine fiber has become an important design tool for filter media. Nanofibers-based filter media have some advantages such as lower energy consumption, longer filter life, high filtration capacity, easier maintenance, low weight rather than other filter media. The nanofibers-based filter media made up of fibers of diameter ranging from 100 to 1,000 nm can be conveniently produce by electrospinning technique. Common filter media have been prepared with a layer of fine fiber on typically forming the upstream or intake side of the media structure. The fine fiber increases the efficiency of filtration by trapping small particles, which increases the overall particulate filtration efficiency of the structure. Improved fine fiber structures have been developed in this study in which a controlled amount of fine fiber is placed on both sides of the media to result in an improvement in filter efficiency and a substantial improvement in lifetime. In the first part of this study, the production of electrospun nanofibers is investigated. In the second part, a different case studyis presented to show how they can be laminated for application as filter media. Response surface methodology (RSM) was used to obtain a quantitative relationship between selected electrospinning parameters and average fiber diameter and its distribution.     

Electrospun nanofibers with application in nanocomposites

The use of fine fiber has become an important design tool for filter media. Nanofibers-based filter media have some advantages such as lower energy consumption, longer filter life, high filtration capacity, easier maintenance, low weight rather than other filter media. The nanofibers-based filter media made up of fibers of diameter ranging from 100 to 1,000 nm can be conveniently produce by electrospinning technique. Common filter media have been prepared with a layer of fine fiber on typically forming the upstream or intake side of the media structure. The fine fiber increases the efficiency of filtration by trapping small particles, which increases the overall particulate filtration efficiency of the structure. Improved fine fiber structures have been developed in this study in which a controlled amount of fine fiber is placed on both sides of the media to result in an improvement in filter efficiency and a substantial improvement in lifetime. In the first part of this study, the production of electrospun nanofibers is investigated. In the second part, a different case studyis presented to show how they can be laminated for application as filter media. Response surface methodology (RSM) was used to obtain a quantitative relationship between selected electrospinning parameters and average fiber diameter and its distribution.     

Carbon Nanotube Penetration Through Fiberglass and Electret Respirator Filter and Nuclepore Filter Media: Experiments and Models

Three different respirator filter media (two electrets and one fiberglass) were challenged with monodisperse multi-walled carbon nanotubes (MWCNTs) of mobility diameters 20–500 nm at 5.3 and 10.6 cm s^?1 face velocities. The penetration data were compared with that of sphere-like NaCl particles. The MWCNT penetrations were generally lower than those of NaCl at both face velocities in all three filters. However, the MWCNTs had a slightly higher penetration than the NaCl in the fiberglass filter at 10.6 cm s^?1 face velocity when their mobility diameters were lower than 50 nm and the alignment effect was expected to occur. Results from the scanning electron microscopic (SEM) analysis supported the hypothesis of the alignment effect, which showed that the MWCNTs tend to be straighter or with higher aspect-ratios at the mobility sizes less than 100 nm, leading them more readily to align with the flow. Therefore, caution should be exercised when respirators are used against the MWCNTs with the mobility diameters less than 100 nm. The single fiber theory predicted the penetration of both particles in the fiberglass filters well for the particles with below 100 nm mobility diameters but discrepancies occurred beyond 100 nm. The theory still predicted the NaCl penetration through the electret filters well for the sizes below 100 nm but only predicted the MWCNT penetration well for ～20–30 nm. The Nuclepore filter and the corresponding capillary tube model were adopted to study the mechanical deposition mechanisms of MWCNTs. The model was found to predict MWCNT penetration very well when the effective length of the MWCNT was taken into account.

Copyright 2014 American Association for Aerosol Research