Wastewater filtration performance of multilayer glassy microporous filters

The glassy composition (quartz, clinoptilolite and frit glass mixture) provides a filter having glassy pore wall microstructure and thus enables easily cleaning through the filter recovery by back flushing. The filter was obtained as multilayer compaction by one step slip cast-processing where a cylindrical filter, consisting of filtration layer on granular assemblies with specific interlayer was shaped by a fine particle migration phenomenon. The multilayer compaction has low resistance to liquid flow and thus the filter great potential to use for wastewater filtration. It is known that high capacity filtration also requires correct pore size/interval with respect to filtered particles. In this study, a wastewater overflow from marble factory (0.035 wt.% of solid with a size distribution of 0.58-1.46 μm) was filtered by different pore sizes of the glassy filters (pore size intervals: 0.4-10 μm, 0.2-4 μm, 0.1-1.5 μm and 0.04-2 μm) and significantly different filtering capacities was obtained; the irreversible fouling capacities were determined between 2.9 and 8.5 m³ of filtrate per m² of the filter area through the filtration produced 5 min intervals. The filtration pressure was 5 bar and backflushing was achieved at 1 bar. The high filterability (8.1 m³/m² in 5 min) with high filtrate clarity (∼0.5 nephelometric turbidity units) could be obtained using finer pore sized filters. The large size filter was seriously clogged during the filtration.     

Preparation and filtration testing of diatomite filtering layer by acid leaching

Ceramic membrane filter consisting of the filtration layer obtained from natural diatomite particles (finer than 50 μm) by coating onto a large porosity support made of quartz-based materials was fabricated. The coating was achieved by pressure filtration at 5 bar and later sintering applied at 600 °C. The sintered product was leached by the hot acid solution (5 M HCl; 75 °C) for 1 h. The characteristic skeletal structure of diatomite (fine microscopic pores) could be obtained without deforming the structural integrity of coating. Filtration response of the filter was tested in dead-end and periodic pressure filtration modes. The filtered particles were of calcite (finer than 1.5 μm) obtained from a marble factory wastewater stream. The diatomite leaching increased the filtration capacity of the filter media more than two times. The filtrate has high clarity (0.1 NTU turbidity). The coating maintained structural stability during a filtration process performed at 5 bar and backflushing of 4 bar.     

Dewatering of coal plant tailings: Flocculation followed by filtration

A sustainable alternative to tailings dam disposal of coal refuse is mechanical dewatering of tailings, which provides fast production of dry solids and water reuse. In this study, flocculation followed by filtration of coal plant tailings, a new concept in tailings dewatering is investigated in detail. This paper focuses on the effect of preconditioning tailings with varying flocculants and dosages on filtration kinetics and the resultant moisture content of the filter cake. The results show that the cationic flocculant, MAGNAFLOC LT 425, requires a high dosage to produce a low moisture content filter cake and clear filtrate. Optimal sized flocs were produced with the anionic flocculant, MAGNAFLOC 5250, even though the particles are negatively charged. The kinetics of the filtration was dependent on the composition of process water as indicated by supporting sedimentation tests. The concentration of divalent alkali earth metals such as Ca²⁺ and Mg²⁺ allow for large floc growth by a bridging mechanism, which involves binding of the polymer and the negativity charged particle. Filtration and settling curves at this dosage were also supported by filter cake analysis using Darcy plots. It was found that the large floc size significantly increases the permeability of the filter cake. Floc size measurements and fractal dimension showed that while the large flocs were produced with anionic flocculant, the flocs produced with the cationic flocculant were small and weak. The results indicate that the optimum dosage and flocculant type for effective and efficient filtration of coal plant tailings is approximately 350 g/t of anionic flocculant at a 35% solids content and 40 kPa filtration pressure.     

水泥厂空压机的节能方法与途径

介绍了空压机节能运行的方法和途径,它包括：加强节能运行管理,采取无功补偿节能,利用变频调速技术节能等措施,为水泥企业空压机安全、高效、可靠运行提供借鉴和参考。     

Design of three-dimensional gradient nonwoven composites with robust dust holding capacity for air filtration

Air pollution has seriously threatened public health in developing countries. However, it is still a big challenge for fabricating a filter with high filtration efficiency, low air resistance, and long service life. Herein, we report a facile strategy to fabricate a multilayered nonwoven composite with a functionally gradient structure for air filtration by a combined method of needle-punch, melt blown, and corona charging techniques. Our integrated multilayer needle-punched/melt blown composite filter could achieve a high filtration efficiency up to 99.52 ± 0.01%, a low pressure drop of 136.87 ± 0.49 Pa, and a satisfied quality factor of 0.03898 ± 0.0001 Pa⁻¹ for sodium chloride particles with an aerodynamic diameter of 0.26 μm at the airflow rate of 85 L min⁻¹. More importantly, the resultant filter exhibited a large dust holding capacity of 23.5 ± 0.41 g m⁻², which indicates a long service life. It is expected that our multilayer needle-punched/melt blown composite fabric may not only serve as a good candidate for air filtration, but also provide a new sight for designing the air filtration materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47827.     

Cross-flow separation of yeast cell suspensions using a sintered stainless steel filter tube

A new design of cross-flow filtration unit, the Transep filter, has been investigated for the separation of slurries of Saccharomyces cerevisiae. Porous cylindrical sintered stainless steel tubes of 2 μm and 3 μm nominal pore size ratings were used as filter media. Filtration rates were measured for cell suspensions ranging from 3 to 25 kg m^?3. The 3 μm filter produced particle-free filtrates at average rates from 1.25 m³ m^?2 h^?1 which declined to half this value over the range of cell concentrations studied.     

Factory’s Dust Emissions Reduced 100 Fold by Centrifugal Filter

Hendrix BV, one of Europe’s leading animal feed manufacturers, was experiencing an ongoing problem at their Antwerp factory with high dust emissions from their pellet cooling operation and with new more stringent EU regulations on the horizon it approached UK company, Global Filtration Systems Ltd, to help reduce their emissions levels. Global Filtration successfully installed its inertial rotary filter, which reduced the density of dust particles in Hendrix’s process gas from 300 mg/m³ down to just 3 mg/m³.     

Industrial experiences of electric filtration in vegetable oil technology

Electric filtration is used to remove bleaching earth and other electrically charged particles from vegetable oils and fats. The grain size of bleaching earth does not significantly influence its separation during application of electric filtration. Therefore, it will be possible to separate bleaching earth with very small grains and increased capability for adsorption. The generation of an electrical field in an insulating fluid is the physical basis of the electric filtration, and under these conditions the generated Coulomb-power moves the bleaching earth grains to one of the electrodes where they will be separated. Electric filtration is available for industrial use. A modular unit enables the testing of all industrial applications directly in the refinery, and it permits the fulfilment of the requirements for the integration of an ÖHMI filtration^® unit in the whole process. Tests on a laboratory and a pilot plant scale have supplied the basis for smooth running of the first industrial plant installed in a large German edible oil refinery. Compact electric filtration plants enable a bleaching earth filtration largely independent of the grain size of the bleaching earth; they reduce the consumption of electric power, they can be adapted to each capacity due to the construction principal of the filter cell moduls, they decrease all expenditure of cleaning and the wear of the filter elements and clothes compared to the conventional cake filtration.     

Enhanced filter elements and housings

The new enhanced DuoFlo^™ filter elements from Cuno can be specified with either polypropylene or polyester filter media, with nominal removal ratings from 1 to 100 microns available.Visit www.filtsep.com for the latest filtration industry news     

Poly(butylene terephthalate) electrospun/melt‐blown composite mats for white blood cell filtration

In this research, poly(butylene terephthalate) (PBT) electrospun nanofibrous mats were prepared for white blood cell (WBC) filtration after the blood was collected from donors. The feasibility of using PBT electrospun mats used as WBC filtration materials was studied. The average fiber diameter and mean pore diameter of the PBT electrospun mats were much lower than those of melt‐blown mats, and such properties were found to be beneficial for the functions of filtration and cell absorbency. A layer of PBT electrospun mats was added before the exit of filter; this formed a kind of compound material with different pore diameters and fibers diameters in the direction of blood flow. The WBC filtration efficiency of the newly designed filter and a traditional filter were also compared. The results show that filters with electrospun PBT fibers reduced the number of WBCs to 10⁴/L, whereas the remaining WBCs after flow through the traditional filter was about 10⁵L^?1. The existence of electrospun fibers increased the filtration resistance at the same time, and this led to a longer filtration time. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

1000 kt/a乙烯装置裂解气压缩机布置及周围配管研究

以天津1000 kt/a乙烯装置为例,从工艺设备布置,压缩机厂房布置及从多因素决定压缩机安装高度、压缩机和汽轮机蒸汽管线布置、管道冲击力等方面介绍大型裂解气压缩机设备布置和配管的设计特点和经验。     

Damage resistant depth filter for biopharmaceutical applications

The new SupraDisc^? II depth filter, from Pall Corp, is intended for the biopharmaceutical market, and has been designed to resist the inherent vulnerability of depth filter discs to damage.This is a short news story only. Visit www.filtsep.com for the latest filtration industry news.     

The Effect of Flocculants and Surfactants on the Filtration Dewatering of Iron Ore Fines

Abstract

The filtration and separation characteristics of iron ore fines have been investigated. The experimental work included: characterization, evaluation of suitable flocculants to enhance settling and dewatering rate, determination of optimum dosages of flocculants, and influence of surfactants on nitration dewatering of both flocculated and unflocculated iron ore fines by vacuum filtration. The results showed that 1) the settling rate can be enhanced many-fold (from 2.52 to 90 m/h) by a suitable flocculant, 2) the residual filter cake moisture content can be reduced from 18.2% without reagents to 12.6% with suitable surfactant dewatering aids while the filtration rate can be enhanced from 4.8 to 97.2 L/h with suitable dewatering filter aids, and 3) the specific cake resistance to filtration can be brought down from 8.6 × 10⁹ to 1.0 × 10⁹ m/kg by using a surfactant sodium petroleum sulfonate at a concentration of 1.47 × 10^?3 kg/t. The economics of using flocculant filter aids and surfactant dewatering aids before thermal drying is described and discussed.     

Removal of corrosion products from viscous aqueous suspensions by magnetic filtration

The removal of micron-sized corrosion products, which may occur during industrial processing by magnetic filtration, has been theoretically and experimentally investigated. The effect of alterations in rheological properties of suspensions carrying particles on magnetic filter performance was determined. Magnetic filter dimensions were 0.03×0.04×0.09 m. The filter was filled with 6.35×10⁻³ m diameter ferromagnetic spheres. Magnetic fields ranging from B=0 to B=1.4 T perpendicular to the flow direction were applied. The suspension flow rate through the magnetic filter was 0.4 m/s. It was determined that 85% of corrosion products show magnetic properties. The magnetic filtration of suspensions composed of water, corrosion products and glycerine at different concentrations was studied. The effects of initial concentration of corrosion products, viscosity of aqueous suspension, magnetic field intensity and the number of filtration cycles on magnetic filter performance were determined. Theoretical and experimental results were in good agreement.     

Welded fabric filter element launched for general filtration duties

At the heart of the new Hayflow filter element, launched by Hayward Industrial Products, is two concentric circles of fabric welded together to form a no-by-pass seam. The fabric is fitted into a metallic basket with a cap on the top and bottom for application in general filtration duties. The Hayflow element is intended as an alternative to conventional bag or cartridge filters and uses a patented Sentinal^® sealing ring to provide a positive seal.Visit www.filtsep.com for the latest filtration industry news     

过滤法分离纯化透明质酸

针对透明质酸的分离纯化,提出了用过滤法分离纯化透明质酸的工艺. 首先以20 g/L的溶解浓度将透明质酸粗品溶于去离子水中,并加入硅藻土作为吸附剂,调节溶液pH至4.6~4.8;然后采用硅藻土过滤、滤板过滤、超滤,用乙醇结晶后可得葡萄糖醛酸含量高达44.2%的透明质酸. 该工艺已成功应用于工业生产,所得产品的葡萄糖醛酸含量达47.3%,蛋白质含量为0.01%,相对分子量可达110万,收率高达90.5%.     

Novel pre-treatment method for seawater reverse osmosis: Fibre media filtration

A high rate fibre filter was used as a pre-treatment to seawater reverse osmosis (SWRO) to reduce membrane fouling. Seawater was drawn from Chowder Bay where the Sydney Institute of Marine Science, Australia is located. A lab-scale fibre filter with a height of 1000 mm and a diameter of 30 mm was used in conjunction with in-line coagulation. The effect of operating the fibre filter with different packing densities (105, 115 kg/m³) and filtration velocities (40, 60 m/h) was investigated in terms of silt density index (SDI₁₀), modified fouling index (MFI), pressure drop (ΔP), turbidity and molecular weight distribution (MWD). The use of in-line coagulation improved the performance of fibre filter as measured by the MFI and SDI. Regardless of filtration velocity and packing density the MFI and SDI₁₀ values remained low as did the turbidity until the end of the filtration run. The MWD analysis showed the removal efficiencies of organic materials like biopolymers, fulvic acids, low MW acids for even experiments with the highest filtration velocity (60 m/h) and lowest packing density (105 kg/m³). This pre-treatment has a small foot print as it has the capacity of operating at a very high filtration velocity.     

WFC9: Exhibitor focus

The WFC9 exhibition is an ideal opportunity for industry professionals to see the latest products and developments in the fields of filtration and separation. Approximately 50 companies are expected to attend the international exposition event in New Orleans, USA, on Monday 19 April to Wednesday 21 April. The 2^1/2 day exhibition runs alongside the short courses and technical presentations that make up the rest of the programme of the ninth World Filtration Congress (WFC9). Below Filtration+Separation presents a selection of new products and systems that will be on display at the Hyatt Regency hotel in New Orleans, covering everything from new netting, radial cartridge filters, membranes, porous metals, and testing/validation equipment to filter presses and antimicrobial filter media. We hope that our Exhibitor Focus section will help you to select the companies and organisations that will be of most interest to you.     

气液过滤过程中液滴二次夹带现象分析

在天然气长距离输送过程中,天然气夹带的液滴严重影响压缩机组的安全可靠运行。利用所建立的滤芯过滤性能检测装置,以癸二酸二辛酯为实验介质,分析了天然气净化用滤芯气液过滤过程中液滴二次夹带现象的特征,比较了滤材润湿性和过滤速度等参数的影响。结果表明:当滤芯仅由聚结层组成时,滤芯过滤过程中存在液滴二次夹带现象,二次夹带将导致下游气体中液滴数量增多,且有较大液滴出现,稳态阶段滤芯累积效率在大粒径处下降;液滴在滤材表面的润湿性对二次夹带现象具有重要影响,可润湿型滤材表面更易出现液滴二次夹带现象,在相同过滤速度下,若需提高过滤效率,宜选用不可润湿型滤材制作工业滤芯;在0.1～0.3 m·s^-1过滤速度范围内,提高过滤速度可减少液滴二次夹带现象的发生,与不可润湿型滤芯相比,可润湿型滤芯过滤效果的改善更为明显;滤芯增加排液层可有效消除液滴二次夹带现象。     

Abtrennung und Extraktion von Bleicherde in geschlossenen Filtern

Separation and Extraction of Bleaching Earth in Closed Filters Application of closed disc filters with centrifugal discharge in filtration and extraction of bleaching earth is described. This type of filter offers advantages, amongst others, those due to exclusion of air and the possibility of extraction of oilcontaining bleaching earth cake “in situ”. Short time interval between starting up and emergence of clear filtrate, and optimum capacities are attained, if pore size of filter membrane is chosen at two to four times the average particle size of solids. Traces of soap contained in the oil have undesirable effect on rate of filtration. It is advantageous to carry out the extraction in two stages, namely, first with dilute miscella, and then with pure solvent. A good quality extracted oil is obtained with hexane as solvent. A combined filtration and extraction plant, attached to an edible fat refinery, consists of 6 filters, each having 20 m² filtration surface. A plant for miscella distillation, and an inert gas plant for generation of protective gas used for compressing, are connected as well. The process is controlled by programmed operation. Filtration capacity of cottonseed oil with 1% bleaching earth with subsequent extraction of filter cake is 340 1/m² · h.