硅藻土-木桨纤维为助滤剂强化过滤过程的研究(英文)

In this paper, a study to enhance the filtration for solid/liquid materials difficult to be filtered, such as highly viscous, highly compactible or gel like materials, is presented. Filter aids diatomaceous earth and wood pulp cellulose are used to enhance the filtration by improving filter cake structure and properties in the filtration of a biological health product and a highly viscous chemical fiber polymer melt product. The property of solid/liquid systems, filtration at different flow rates, specific cake resistance, cake wetness, filtration rate, filtrate turbidity for filter aid selection and evaluation, and operation optimization are investigated. The results are successfully applied to industrial process, and can be used as a reference for similar filtration applications.     

多管陶瓷过滤器内耦合效应数值模拟

The Reynolds stress transport model and the Eulerian two-fluid model provided by the FLUENT code were applied to evaluate the gas-particle two-phase flow in the ceramic filter vessel. The ceramic filter vessel contains six candle filters, which are arranged in the form of equilateral hexagon. The variation of the areal density of the filter cake during the filtration and the back-pulse process were analyzed. The coupling effect between filters, gas and solid, filtration and pulse cleaning process were investigated, respectively. The numerical results show a good approach to predict the particle distribution in the vessel and the particle deposition on the filter element. This study provides the base for the intensive study on the analysis of the gas-particle flow in the filter vessel.     

操作温度对褶皱型不锈钢编织型过滤器阻力特性的影响

Effect of working temperature on the resistance characteristic including the permeability coefficient and the pressure drop evolution of a pleated stainless steel woven filter with a nominal pore size of 0.5 μm has been studied. The permeability coefficient was obtained based on the pressure drop data and the Darcy’s law. In three filtration experiments, pure carbon dioxide at 283 K, nitrogen at 85 K and liquid helium at 18 K are adopted, respectively. It is found that the permeability coefficient decreases at the working temperature due to the cold shrink of the filter element at cryogenic temperature. Then, two kinds of feed slurries, mixture of liquid nitrogen and solid carbon dioxide at 85 K, and mixture of liquid helium and solid nitrogen at 18 K, flow into the filter cell. The solid particles are deposited on the filter surface to form a filter cake and the purified liquid flows through the filter. It is found that the pressure drop evolution shows the same trend on these two temperatures, which can be divided into three stages with high filtration efficiency, indicating the feasibility of the filter for cryogenic application. However, variant cake resistances are obtained, which is resulted from the different interactions between solid particles in the feed slurry at lower working temperature.     

陶瓷过滤管表面粉尘层清除过程的图像分析

Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the reservoir pressure, and the filtration velocity on the cleaning effectiveness are analyzed. Experimental results show that there exists an optimum dust cake thickness for pulse-cleaning process. For thin dust cake, the patchy cleaning exists and the cleaning efficiency is low; if the dust cake is too thick, the pressure drop across the dust cake becomes higher and a higher reservoir pressure may be needed. At the same time there also exists an optimum reservoir pressure for a given filtration condition.     

A free-standing superhydrophobic film for highly efficient removal of water from turbine oil

A free-standing superhydrophobic film is prepared by sequentially dip-coating a commercially available filter paper with nano SiO2 suspension, epoxy emulsion, and octyltrimethoxysilane solution. A surface with micro- or nano-roughness is formed because SiO2 nanoparticles are uniformly and firmly adhered on the backbone of the filter paper by the cured epoxy resin. Furthermore, the surface energy is significantly reduced because of introducing octytrimethoxysilane. Such a surface structure makes the prepared film a superhydrophobic material. Due to its free-standing nature, this superhydrophobic film can be used to remove water from turbine oil by filtration. The efficiency of water removal is high (up to 94.1%), and the filtration process is driven solely by gravity without extra energy consumption. Because of the facile fabrication process and the high efficiency of water removal, this free-standing superhydrophobic film may find application in power industry.     

关于过滤理论与滤饼可压缩性的探讨

This paper gives a study on the rates of filtration and cake formation and filter cakes permeability and compressiblity．A new calculating equation of filter cakes special resistance is advanced，It indicates that the permeability of filter cake is not only related with slurry concentration and its settling velocity，but also related with the pretreatment and chemical environment of slurry．     

恒压过滤介质阻力分析

A mathematical model for constant pressure filtration is established. The distribution of hydraulic pressure within the cake and the medium resistance are measured. The medium resistance Rm is calculated from the suppositional filtration time Ore. It is demonstrated that Rm is nearly a constant for a given filter cloth.     

Soap-based detergent formulations: XX. The physical and chemical nature of lime soap dispersions

Blends of soap and surfactants that possess good lime soap dispersing properties were dispersed in hard water. The turbidity of such dispersions varied depending on the type of dispersant used and also on the soap:dispersant ratio. Differences in coarseness of various dispersions could be measured empirically by filtration through a membrane of intermediate (1.2 μm) porosity. For determinations of the chemical composition of the dispersions a somewhat finer membrane (0.8 μm or less) was chosen, which retained most of the dispersed solids. Filter residues and filtrates were analyzed for sodium, calcium, magnesium and lime soap dispersing agents (LSDA). All of the calcium remained on the filter, whereas sodium was found primarily in the filtrate. Magnesium was held completely on the filter only if sufficient soap was present to tie up all Ca⁺⁺ and Mg⁺⁺. Analysis of the organic portion of the residues indicated that the soap:LSDA ratio found was the same as that used in the preparation of the original dispersion. On filtration through a fine membrane (0.05 μm) virtually all dispersed material was retained on the membrane. The filtrate possessed only slight activity in terms of surface tension and detergency, whereas the resuspended solids possessed high surface activity similar to the unfiltered dispersion. This indicates that the dispersed solids are the major source of surface activity. Presented at the AOCS Meeting, September 1975, Cincinnati.     

从工业角度透视纤维介质在气溶胶过滤上的应用(英文)

Filtration of aerosol particles using non-woven fibrous media is a common practice for air cleaning. It has found wide applications in industries and our daily lives. This paper overviews some of these applications and provides an industrial perspective. It starts from discussing aerosol filtration theory, followed by a brief review on the advancement of filtration media. After that, filtration applications in respiratory protection, dust collection, and engine in-take air cleaning are elaborated. These are the areas that the author sees as the typical needed ones in China’s fast pace economical development endeavor, where air filtration enables the protection of human health, environment and equipment for sustainability.     

CROSS-FLOW FILTRATION OF FUNGAL SUSPENSION WITH REVERSED-FLOW CLEANING

The separation of fungal suspension Trichoderma reesei was studied by using cross-flow filtration(CFF)with re-versed-flow cleaning(RFC)technique.The advantage of this technique is demonstrated in comparison with other filtra-tion techniques.The filtration rate is influenced by different frequencies of RFC.For optimum combination of CFF andRFC,both experimental and theoretical considerations are necessary and are discussed.An expression has been derivedfor the optimum filtration time needed to maximize the flux for a given RFC period assuming that the filtration stage canbe approximated by Ruth’s equation.The practical usefulness of this calculation is demonstrated on a batch thickening op-eration.     

Advances in the Precoat Filtration Process

Abstract

Precoat filtration with body‐feed is widely applied during wine‐making. This technique employs filter aids, such as diatomites (silica particles), to form the precoat layer. However, the spent diatomites, which retain organic matter, represent an important source of pollution and land disposal of this type of waste is forbidden. In addition, these spent diatomites are not regenerable. The aim of this study was to evaluate regenerable filter aids which have a high environmental acceptability. Polyamide particles were characterized as filter aids, tested in precoat filtration and compared to diatomites which are the classic filter aids used in wine filtration.

Polyamide particles seemed to be efficient filter aids, reducing turbidity by 72% and the fouling index by 56% without affecting wine quality.     

精细过滤及硅藻土助滤剂的应用

采用硅藻土助滤剂应用于工业精细过滤,可提高过滤质量和过滤能力,并能扩大过滤机的适用范围。介绍了应用硅藻土助滤剂过滤操作的三种方式以及硅藻土过滤机的类型及特点和硅藻土的过滤性能。     

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.     

分子筛浆料助滤技术的开发和应用

通过建立分子筛浆料过滤速率的测定方法,对四种分子筛浆料的固液分离、交换和洗涤过程的过滤速率进行了研究,开发的四种助滤剂可有效改善不同分子筛的固液分离、交换和洗涤过程的过滤速率。这四项助滤技术已在三家国内主要的裂化催化剂厂广泛的得到应用,使带式过滤机彻底取代了板框过滤机,解决了企业生产中长期存在的瓶颈问题。     

Regeneration of oils used for deep frying: A comparison of active filter aids

A number of products are promoted for the purpose of regenerating used frying oils. These materials are referred to as “active” filter aids. They are purported to adsorb polar compounds, which are the products of oil degradation, and to retain them for removal by filtration. To evaluate some of these materials, portions of a used oil were treated with each of several “active” filter aids and filtered in a commercial-type recirculating oil filter. The triglycerides and any adsorbed compounds were extracted from the filter cake with a series of increasingly polar organic solvents. The composition of each of the filter cakes was quantitatively determined. The materials tested in this study were diatomaceous earth, acid-activated bleaching earth, activated aluminas, silica, carbon and synthetic magnesium silicate. Significant differences in the adsorbent characteristics of the materials were found. Adsorption of polar oil degradation compounds ranged from 2 mg of polar compounds per gram of diatomaceous earth to about 200 mg/g magnesium silicate.     

选煤厂浮选精煤助滤脱水实验研究

针对赵固二矿选煤厂浮选精煤水分偏高的问题,采用添加助滤剂的手段降低浮选精煤水分,分别进行助滤剂的选型实验和定量实验。选型实验结果表明,液体助滤剂比固体助滤剂更能显著降低浮选精煤水分和缩短抽滤时间,因此选用液体助滤剂进行定量实验。定量实验结果表明,TLT5140助滤剂的整体效果最佳,并且在药剂用量为80 g/t时,浮选精煤水分可降至16.5%左右。最终选用TLT5140助滤剂进行工业实验,与不加药剂相比,浮选精煤产品水分降低3%,加压过滤机排料周期缩短50%。助滤剂的使用降低了浮选精煤水分,提高了过滤设备的生产能力,满足了客户对最终精煤水分的要求。     

Clarification of liquids using filter aids Part I. Mechanisms of filtration

Filter aids were characterized by an effective particle diameter and a pore diameter in the filter aid cake, calculated from the specific cake resistance using the Kozeny equation. The results agreed well with those from mercury porosimetry. The transition from surface filtration to depth filtration by filter-aid cakes was studied with uniform polystyrene particles as a model impurity. The critical ratio between pore diameter and impurity diameter was between 2 and 3. At conditions of non-surface filtration, an important concentration of impurity exists in the liquid flowing through the cake causing a danger of blocking. When pre-coat and body feed were used with polystyrene particles as an impurity, the blocking appeared to occur rather easily on top of the original pre-coat and on the filter medium. The type of pre-coat and the way in which it was formed were very important. In beer filtration, which is mainly a surface filtration, a small concentration of passing impurity was able to block the pre-coat layer, when the filter aid of the body feed was coarser than that of the pre-coat.     

Labortest zur Minimierung des Versuchsaufwandes bei Pilotfiltrationen

Investigating beer filtration using cellulose fibers requires appropriate methods. One aspect is the preparation of large scale trials. Starting from the filterability test according to Raible and based on the results of diverse pilot scale trials, a laboratory test was created. Apparatus, procedure and methods of assessing the results are described. The new test is qualified for reducing time and effort in upper scale trials, especially in case of varying filter aids compositions.     

Why adding rice hull ash can benefit beer clarification

Filter aids continue to play an important role in the beer brewing process. The majority of commercial products are either diatomite- or perlite based. However, rice hull ash, a by-product from the incineration of rice hulls, has been shown to be an effective filter aid in the filtration of raw sugar liquors. A research team from the Cuban Research Institute of Sugar Cane Derivatives (ICIDCA) has gone on to investigate its ability to clarify beer. The findings of their study are presented below.