THE STUDY OF THE FILTRATION EFFICIENCY OF FILTER MATERIAL

In this paper, the course of the filtration is analyzed.In order to study the filtration efficiency of the filter material, the computer program was edited.According to the results of the computer program, some important parameters of the filter material are discussed.It shows that the filtration efficiency is closely related to the diameter (d) and the size (b) .In addition, by using these results and the computer program, we can analysis the relationship between the fiber structure and filter properties quantitatively.

Efficiency characterization of ceramic filtering materials used for drinking water treatment

For ceramic filtering materials, their adsorption capacities, purification efficiencies to remove organic compounds from drinking water, and correlation between adsorption capacities and pore structures were tested and analyzed. The results show that correlation coefficient between the specific surface area and the adsorptive amount of iodine molecule is 0.99; correlation coefficient between the pore volume and the adsorptive value of tannin molecule is 0.92, and correlation coefficient between the most probable diameter and the adsorption parameter is 1.0. A new method of morphology characterization for ceramic filtering materials was developed, which offered a sort of standard for the evaluation on water purification efficiencies and selection of ceramic filtering materials.

A Fast Predicting Neural Fuzzy Model for Suspended Solid Removal Efficiency in Multimedia Filter

Modeling of filter performance is very difficult because of complexity of the defining physical and chemical events in the filtration system whereas the knowledge of functionality of filter coefficient. The main objective of this study is to predict the performance of multimedia filter and to evaluate both the initial and transient stage of suspended solid removal efficiency depending on experimental data. Fuzzy logic has been used to build a model of multi input and one output (MISO) for the removal efficiency of multimedia filter which it consists from sand and granular activated carbon (GAC) mediums. The control parameters of (FLC) of Sugeno model are seven parameters which are media depths, media grains size for both sand and GAC, filtration rate, diameter of suspension particle, feed concentration, and operation time. The output parameter is removal efficiency of media filter whereas these data are collocated from pilot scale deep bed filter, thus, the removal efficiency of filter was modeled by 575 rules as a function of different control parameters. An adaptive of neuron fuzzy inference system (ANFIS) had used to simulate the experimental data. The simulation results were evaluated using mean absolute percentage error (MAPE), whereas the results showed that the prediction of ANFIS model has a good agreement with experimental data when the MAPE is equal to 7.0458 and fuzzy rule -based modeling proved a reliable and flexible tool to study the performance of multimedia filter. The conclusion showed that there is a relationship between flow rate, effective size and optimum bed depth for all filter media, the increment of effective size generates a higher value of optimum filter bed depth for a lower value of filtration rate. It was concluded that the optimal removal efficiency (95-100) achieved by (0.5-0.7 mm) grain size of sand, (1.5-1.9) mm grain size of granular activated carbon (GAC), with media depths should range from 0.3 to 0.6 m.

Preparation of High-precision Electrospun Nanoair Filter Paper for Air Purification

Electrospinning technology has become a research hotspot becauseof its advantages, such as simple operation, low cost, large specific surfacearea, high porosity, and good fiber continuity. Here, a new type of compositenanoair filter paper was prepared using electrospinning technology. Toimprove the practicability of air filter base paper, phenolic resin was used as acuring agent to improve the strength. The results show that the electrospunnanoair filter paper with air filter paper as the receiving substrate andpolyvinyl alcohol (PVA) solution as the spinning solution excellentlyperformed in all aspects. The influence of the thickness (spinning time) of thePVA nanofiber membrane on the micromorphology, physical properties, andfiltration performance of the electrospun nanoair filter paper was analyzed.According to the ISO 5011-2014 standard, the initial resistance, filtrationefficiency, mean pore size, and dust capacity of the electrospun nanoair filterpaper were 77.3 Pa, 99.9941%, 3.50 μm, and 146 g/m^(2), respectively, when thespinning time was 15 min.

Filtration characteristics of granular bed with layered drawers for removing dust from gas streams

Filtration tests were conducted on a granular bed filter with layered drawers filled with corundum particles with sizes between either 1 mm and 1.5 mm or 2 mm and 3 mm or with quartz sand particles with sizes between 0.125 mm and 1.5 mm.Filtration velocity,filter particle thickness,and filter particle size were all found to influence the filtration efficiency and the pressure drop of both the fixed granular bed and the layered-drawer granular bed.Granular strata with different thickness ratios also strongly influenced the filtration efficiency and pressure drop.For a granular bed with two sizes of filter particles,the coarse granules in the upper layer capture dust with large particle sizes,while the fine granules in the lower layer capture dust with smaller particle sizes that passes through the filter cake and upper layer.Optimal operating conditions were determined at which the filtration efficiency was found to be 99.42%with a bed pressure drop of 320 Pa.

基于壳聚糖的复合抑菌空气滤料制备与评估

由于新冠疫情的暴发,人们对于室内空气质量有了更高的要求.探索既能过滤细微颗粒物,还能抑制和消杀微生物细菌、防止二次污染的过滤材料具有重要意义.以质量分数为1%的聚四氟乙烯(PTFE)乳液配制出不同壳聚糖质量浓度的浸渍液,利用直接浸渍后处理工艺制备出壳聚糖/涤纶/聚四氟乙烯复合抑菌空气滤料.利用大肠杆菌为实验菌落验证其抑菌性能,并对其织物特性、捕集效率及压差特性进行了研究.结果表明,壳聚糖质量浓度为12.5 mg/mL时复合滤料初始阻力最小,对PM_(2.5)粒子捕集效率达到93.88%,品质因子为0.02013,分别比原始滤料提高19.56%,0.0044,且对大肠杆菌的抑菌率为84.12%.综上所述,壳聚糖质量浓度为12.5 mg/mL,PTFE乳液质量分数为1%的浸渍液制备的壳聚糖/涤纶/聚四氟乙烯复合抑菌空气滤料兼具良好的过滤能力与抑菌效果.

气固逆流式移动床过滤器的实验研究

为探究操作条件对气固逆流式移动床过滤器过滤性能的影响,通过大型冷模实验,考察了气固逆流式移动床过滤器的捕集颗粒循环强度、入口粉尘浓度、表观气速及入口粉尘粒径对装备性能的影响。实验结果表明,表观气速是影响床层压降的主要因素,表现出正相关的趋势。捕集颗粒循环强度、入口粉尘浓度、粉尘粒径的改变对床层压降影响较小。捕集颗粒循环强度和入口粉尘浓度的增加使压降增加。而粉尘粒径与床层压降间的关系随时间变化,开始时粉尘粒径与压降呈正相关,但当装置运行至平稳阶段则趋于降低。装备的除尘效率与入口粉尘浓度及颗粒循环强度正相关,与粉尘粒径及表观气速负相关。但粉尘粒径越小过滤效率越高的趋势受装置内滤饼的影响,仅在粉尘中位粒径10μm以上,且入口粉尘质量浓度在0~32 g·m^(-3)出现。移动床过滤器保持稳定床层压降的同时,具有较高的除尘效率。在颗粒循环强度0.3119 kg·s^(-1),16.5~32.7 g·m^(-3)入口粉尘浓度条件下,除尘效率可达99%;且对细微(13μm以下)粉尘的粒级效率接近99.9%。

外加电场作用下颗粒层除尘器过滤性能的数值研究

【目的】研究外加电场和细颗粒物粒径对固定床颗粒层除尘器(granular bed filter,GBF)过滤性能的影响。【方法】建立GBF的三维过滤模型和电场力模型并验证其准确性;研究有、无外加电场及不同电场强度情况下GBF对粒径为1~21μm的细颗粒物的过滤情况,并分析不同粒径的细颗粒物在GBF内部的分布规律。【结果】外加电场的存在能显著提高GBF对粒径为3~21μm的细颗粒物的过滤效率,且外加电场强度越大,细颗粒物粒径越大,GBF过滤效率提升越明显;随着粒径的增大,细颗粒物在堆积颗粒层内部的分布更加集中在高气流速度区域,且更容易通过堆积颗粒层与GBF壁面之间形成的通道;外加电场的存在使得堆积颗粒层内部的细颗粒物数量减少,分布散乱,且大粒径细颗粒物在GBF壁面附近区域发生较大规模聚集。【结论】外加电场和细颗粒物粒径的增大与GBF内部细颗粒物的分布规律密切联系,且对GBF过滤性能的提升发挥积极作用。

柴油/聚甲氧基二甲醚混合燃料匹配催化型颗粒捕集器的排放特性研究

使用柴油和聚甲氧基二甲醚(polymethoxy dimethyl ether,PODE)混合燃料进行了柴油机催化型颗粒物捕集器(catalytic diesel particulate filter,CDPF)的排放特性试验,研究分析了添加PODE对CDPF的过滤效率及CDPF前后端NO_(x)、CO_(2)和颗粒物排放变化的影响。结果表明:加入PODE提高了CDPF对颗粒物的过滤效率,使用90%体积分数的柴油与10%体积分数的PODE掺混(D90P10)可使CDPF的平均过滤效率提高3.6%。CDPF对核态颗粒物的过滤效率低于86.39%,CDPF对聚集态颗粒物的过滤效率高于91.32%,CDPF对核态的过滤效率低于聚集态。CDPF对不同粒径颗粒物的过滤效率不同,且随颗粒物粒径的增加而增加。两种燃料下,通过CDPF后的颗粒物的几何平均直径(geometric mean diameter,GMD)均减小,NO_(x)排放降低,CO_(2)排放增加。

复合改性砂滤料制备及生物砂滤池对受污染原水的净化效果

为改善普通石英砂(QS)表面特性,提高生物砂滤池生物附着量及对水中污染物的去除效果,对QS进行氨基、铝离子及铝钙双氢氧化物改性,制得氨基改性砂(AMS)、铝离子改性砂(ALS)和铝钙双氢氧化物改性砂(CAS),以四种滤料填充滤池考察对受污染原水的净化效果。结果表明,与QS相比,ALS与CAS表面覆盖了金属离子,AMS、ALS、CAS表面形态及比表面积均得到改善,成膜后表面生物附着量分别增加3.6、5.5、6.9 mg/g;滤速为5 m/h时,CAS滤池对浊度和COD平均去除率分别为90.1%、51.8%。与AMS、ALS滤池相比,CAS滤池表面生物量最大,对水中污染物去除效果良好。

基于静电纺PAN/PMIA共混纳米纤维复合空气过滤纸的制备及性能研究

以空气过滤原纸为基材,高可纺性的聚丙烯腈(PAN)和高性能间位芳纶短切纤维(PMIA)为原料,利用静电纺丝技术,制备PAN/PMIA共混纳米纤维复合空气过滤纸。通过调整2种特种纤维的质量比,制备具有良好过滤性能和较好耐高温性能的复合空气过滤纸。结果表明,PAN与PMIA质量比为3∶7的PAN/PMIA共混纳米纤维复合空气过滤纸的过滤效率为99.995%,初始阻力为79.01 Pa,容尘量为175 g/m^(2)。经一系列热处理后,复合空气过滤纸的过滤效率可保持在99.960%以上。

3种滤料对池塘圈养尾水处理效果的影响

为了探究过滤材料用于池塘圈养尾水的处理效果,采用火山岩、活性炭及沸石作为过滤材料,以滤料种类、滤料粒径和滤料厚度为试验因素,以总固体悬浮物(total suspended solid,TSS)去除率、氨氮(NH_(4)^(+)-N)去除率和化学需氧量(chemical oxygen demand,COD)去除率为试验指标,开展池塘圈养尾水处理试验。结果显示,3种滤料均能去除池塘圈养尾水中的TSS和COD,均能在一定程度上降低池塘圈养尾水中的NH_(4)^(+)-N浓度,活性炭的处理效果优于其他2种滤料,且活性炭粒径越小或厚度越大时对池塘圈养尾水处理效果越好。正交试验结果显示,以活性炭滤料、粒径为0.5~2 mm、滤料厚度为80 cm时,过滤装置对池塘圈养尾水具有最佳的综合处理效果,在该条件下对池塘圈养尾水的TSS、COD、NH_(4)^(+)-N去除率分别为83.86%、49.78%、29.89%。

PTFE针刺毡滤料覆膜牢度研究

随着环保标准的不断提高,国家对工业烟气中微细颗粒物的排放提出了更高的要求。目前,工业除尘滤料中基于聚四氟乙烯(Polytetrafluoroethylene, PTFE)膜的覆膜针刺毡滤料对微细颗粒物有较高的过滤效率。然而,PTFE膜在长期使用过程中有脱落的风险,进而影响除尘器的除尘效果。因此,PTFE膜与针刺毡滤料基底间的覆膜牢度至关重要。研究选取市场上常用的5种PTFE覆膜滤料,对其覆膜牢度进行系统评估,并分析覆膜牢度的影响因素。结果显示:同样以PTFE为基底的覆膜滤料的覆膜牢度最大,其值大于0.074 MPa;以芳纶、聚酰亚胺(Polyimide, P84)、聚苯硫醚(Polyphenylene Sulfide, PPS)针刺毡滤料为基底的覆膜滤料覆膜牢度为0.027~0.029 MPa。经分析,覆膜的处理温度对覆膜牢度有较大影响,而实际处理温度需根据针刺毡基底的材质选择;针刺毡基底表面的纤维面积占比也是影响覆膜牢度的因素之一。此外,研究对膜脱落后滤料的过滤性能变化进行评估发现,膜脱落对滤料过滤性能有较大影响,其中P84覆膜滤料的膜脱落后过滤性能变化幅度最大,对PM2.5的过滤效率由95.25%降低至78.66%。研究成果对覆膜滤料的选择以及增强覆膜滤料的覆膜牢度具有指导作用。

基于级配滤料的含聚污水过滤-反冲洗运行模式优化

随着聚合物驱三次采油技术的广泛应用,含聚污水已成为油田采出水处理的难点,采用双层或多层级配滤料,以及改变滤料层间级配填充高度比,被认为是改善含聚污水处理效果的一种有效手段。文章基于污水处理站以石英砂和磁铁矿为主要滤料选型的运行实际,从层间级配滤料不同填充高度比关系出发,数值模拟研究了含聚污水过滤-反冲洗过程,揭示了层间级配滤料对过滤-反冲洗性能的影响,并结合实验验证,对含聚污水过滤-反冲洗运行模式进行了优化。结果表明,含聚污水过滤过程中压力场的显著性波动特征集中出现在滤料层区域,随着填充高度比的减小,自滤料层上部区域转向滤料层深部区域,同时,适当增加磁铁矿滤料层厚度,有利于悬浮粒子在滤料层中的去除;反冲洗过程中,当石英砂滤料层的填充厚度增加时,滤料层颗粒运动行为更为显现,更有利于附着在滤料颗粒表面悬浮粒子的脱附;推荐以1.67~2.20填充高度比的层间级配模式过滤低含聚浓度污水、以1.28~1.67填充高度比的层间级配模式过滤高含聚浓度污水。研究结果为含聚污水提效过滤处理过程中层间级配调整方案的设计与实施提供了依据,也为滤料选型及多层级配方案的优化与设计提供了基础。

矿用湿式过滤除尘器过滤单元过滤技术优化研究

为提升矿用湿式过滤除尘器呼吸性粉尘除尘效率,以除尘器过滤单元过滤参数为实验对象,搭建过滤单元实验平台,研究除尘器过滤单元过滤形式、过滤网层数/除雾垫厚度、孔径、过滤风速等对呼尘除尘效果和阻力的影响规律。研究结果表明:相同条件下,10层20目金属过滤网过滤板过滤性能最佳,阻力1 370 Pa,呼尘除尘效率90.7%;过滤风速取7.8 m/s,除尘器呼吸性粉尘除尘效率最高;采用冲击式惯性分离器与滤网融合设计的过滤板能有效避免出现堵死导致除尘器风机损坏。研究结果可为优化矿用湿式过滤除尘器结构、提升呼尘除尘效率提供依据。

除尘脱硝一体化滤料的制备及其性能研究

以硝酸铈、偏钒酸铵等为主要原料,通过加热搅拌混合制备催化剂前驱体浆料,并采用表面浸渍法将浆料负载到基材滤料,通过压延、干燥、煅烧形成除尘脱硝一体化滤料。研究了浸渍方式、过滤风速和负载量对除尘脱硝效率的影响,并验证了滤料的催化剂稳定性、耐磨性能和抗水、抗硫、抗碱、中毒性能。通过SEM、XRD表征分析,结果表明:在二步浸渍法负载滤料负载量为352 g/m2,过滤风速为0.4 m/min时,在160℃~220℃温度区间内,脱硝效率为60%~95%,0.6 MPa的喷吹压力下,表面催化剂损失率仅1.1%。滤料的耐磨性能和过滤性能优于常规滤料(在1μm粉尘粒径过滤下,过滤效率可达99.87%),具备良好的抗水、抗硫、抗碱金属性能。

工业烟尘过滤用水刺玻纤复合滤料性能研究

对水刺工艺和针刺工艺两种不同生产工艺制得的玻纤复合滤料进行性能测试与对比。结果表明:水刺工艺对玻纤的损伤小;水刺玻纤复合滤料的挺度值低,耐折性能好,可减少纤维原料使用量;过滤性能方面,水刺玻纤复合滤料的残余阻力低于针刺玻纤复合滤料的,过滤效率则高于针刺滤料的。

Experimental Investigation of a Cryogenic Filter for Separating Solid Carbon Dioxide Particles from Liquid Nitrogen

This paper presents an investigation of a new method of purifying cryogenic liquid using sintered metallic wire-mesh filter,which has the advantages of high purifying efficiency and preferred strength at absolutely low temperature.Experiments are conducted to purify solid CO_2 particles from liquid nitrogen.Temperature and pressure in the upstream and downstream of the filter,and the flow rate of carbon dioxide(CO_2) gas and liquid nitrogen are measured,with the gas content of filtrate analyzed using a CO_2 concentration detector.It is illustrated that after filtration,the purity of liquid nitrogen(volume fraction) is higher than 99.99%,which means that the volume fraction of CO_2 is less than 0.01%.Effects of operation parameters on the performance of the filter,such as pressure drop△p and filtration efficiency E are analyzed quantitatively.The present conclusions will provide a guideline to the optimumal design and operation of sintered metallic wire-mesh filter in cryogenic application.

金属丝网多孔材料研究进展

金属丝网多孔材料是一类孔隙可控、高比表面积、高强度、价格低廉的多孔材料,由于具有高透气性和高过滤精度,在高温烟气、油浆等过滤分离领域得到了广泛应用。由于金属丝网多孔材料同时具有高比表面积、开孔特性、高孔隙度、高强度和孔隙可逐级调控等特性,在光催化、机车尾气净化、高效换热、爆燃冲击防护等领域得到重视。本文介绍了金属丝网多孔材料的结构及制备方法,着重总结了金属丝网多孔材料在过滤分离、催化、高效换热、爆燃防护等领域的应用进展,并对其应用前景和发展方向进行了展望。

芳纶1414针刺非织造滤材的制备及性能研究

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