刚性过滤器脉冲反吹过程中滤管内动态压力特性

催化汽油吸附脱硫（S-Zorb）装置中反应器过滤器的脉冲反吹性能直接影响吸附剂的分离与循环。利用建立的滤管过滤性能实验装置,采用高频动态压力传感器,测定脉冲反吹过程中沿滤管长度方向不同位置处滤管内动态压力随时间的变化特性,分析了滤管长度、反吹压力和脉冲宽度对滤管内动态压力特性的影响规律。结果表明：自开口端至盲端,滤管内动态压力的压力峰值先逐渐变大后基本不变;相同反吹条件下,随着滤管长度的增加,滤管内沿长度方向各位置处的压力峰值均降低。实验范围内,1750～2000 mm滤管开口端附近的动态压力在达到压力峰值后降低为负压,并在反吹气流和脉冲压力波的共同作用下持续振荡。适当提高反吹压力以及增加脉冲宽度可以改善长滤管的反吹效果。     

滤料清洗剂的研制与应用

油田污水过滤系统的滤料表面主要吸附的污物有油污、悬浮杂质、细菌及其产物、硫化亚铁、氧化铁、水垢及三次采油用聚合物等,滤料清洗温度低、难度大,以往的清洗剂除油率低,难以满足生产现场需要。针对油田污水过滤系统中滤料的清洗,依据表面活性剂清洗原理,通过实验与筛选,研制出的滤料清洗剂配方,具有低温低泡沫、高效除油、良好的配套性、经济环保等特点,除油率大于95％,经油田现场应用完全符合生产要求。     

Origin and mechanisms of dust emission from pulse-jet cleaned filter media

The respective contributions of direct particle penetration vs. particle reentrainment to emissions of pulse-jet cleaned filter media were measured for needle felts of different construction, in combination with two particle materials, one free-flowing and one agglomerating. Different media conditioning protocols (including accelerated aging up to 20,000 pulses) were applied as well, in order to simulate longer-term use of the filters.With about 96-99% of emissions per cycle, direct particle penetration was by far the dominant mechanism under all circumstances. The size distribution of emitted particles was centred narrowly around the MPPS between 0.5 and 1 µm, and tended to shift toward finer particles with progressive media aging, much like in a depth filter. The total reentrained dust mass per cycle was on the order of 10^− 5 of the mass stored inside the medium. Cross-sectional analysis of a few media by electron microprobe indicates that the support scrim may act as an effective barrier to particle seepage more than to direct penetration.The well known increase in emission level with cleaning pulse intensity can be attributed to a slowing-down or prevention of the clogging process, rather than enhanced reentrainment of stored dust. Earlier reports of increased emissions at higher filter face velocities are probably due to the redeposition of dust from the filter cake immediately after a cleaning pulse.     

Computer program for filter media design optimization

This paper presents a computational approach for designing, mixed fiber filter media for depth filtration. The goal is to find an optimum solution, given the range, for a set of design parameters: thickness of the media, diameter of microfiber, and diameter of nanofiber, surface area ratio of nanofiber to microfiber and mass of microfiber. The objective of this work is to develop a software program that can be used as an aid to accelerate filter design and reduce the number of laboratory experiments.This program applies a Genetic Algorithm to search for an optimum filter media design based on quality factor which quantifies the filter performance. A user friendly computer program is developed that provides inputs, outputs and controls to design a filter media. The program provides a starting point for constructing filter media for testing and design for particular applications.     

Capillarity in fibrous filter media: Relationship to filter properties

This work examines the wetting of a range of low packing density (high porosity), porous, fibrous media by mineral oils. The fibrous media were suspended above a vessel of oil, and the rate of imbibation of oil was measured by means of a balance under the oil and a load cell above the media. It was found that the height of the oil column within the media over time generally resembled the classical capillary rise curve. Capillary rise models were fitted to the data to predict an equivalent capillary diameter, dynamic contact angle, and height of the liquid column as time approaches infinity, using the known filter and oil properties. Different capillary models were examined, and it was found that the modified Washburn equation was the simplest model to use and produced an acceptable agreement between theory and experiment. It was found that the adjustment phase of the curve from the fibrous media was generally more rapid than for a typical capillary, presumably since the fibrous media can be wetted not only from directly below (as with a capillary), but also through the meniscus at the sides of the media. It was found that a linear correlation existed between the effective capillary diameter of the media, and the packing density of the media divided by the fibre diameter. The results appear to be relatively independent of the material type. These results allow capillary diameters to be determined for fibrous media from easily measured parameters, without the requirement of conducting wetting experiments or ‘bubble-point’ tests.     

Recent developments on catalytic membrane for gas cleaning

Catalytic membrane, a novel membrane separation technology that combines catalysis and separation, exhibits significant potential in gas purification such as formaldehyde, toluene and nitrogen oxides(NO_x). The catalytic membrane can remove solid particles through membrane separation and degrade gaseous pollutants to clean gas via a catalytic reaction to achieve green emissions. In this review, we discussed the recent developments of catalytic membranes from two aspects: preparation of catalytic membrane and its application in gas cleaning.Catalytic membranes are divided into organic catalytic membranes and inorganic catalytic membranes depending on the substrate materials. The organic catalytic membranes which are used for low temperature operation(less than 300 °C) are prepared by modifying the polymers or doping catalytic components into the polymers through coating, grafting, or in situ growth of catalysts on polymeric membrane. Inorganic catalytic membranes are used at higher temperature(higher than 500 °C). The catalyst and inorganic membrane can be integrated through conventional deposition methods, such as chemical(physical) vapor deposition and wet chemical deposition. The application progress of catalytic membrane is focused on purifying indoor air and industrial exhaust to remove formaldehyde, toluene, NO_x and PM2.5, which are also summarized. Perspectives on the future developments of the catalytic membranes are provided in terms of material manufacturing and process optimization.     

Wettability studies of filter media using capillary rise test

Filtration process is a typical tertiary treatment method for oily wastewater, suitable for the lower oil concentration and oil-in-water emulsion system. Therein the wettability of oil-in-water emulsions to filter media probably has some significant influences on the oil removal efficiency, namely a lipophilic filter medium have a better performance in oil droplets coalescence and attachment than a hydrophilic one. In this paper, a Lipophilic to Hydrophilic Ratio (LHR) concept was defined on the basis of Washburn's equation and a test equipment was correspondingly designed, which were used to compare quantificationally the wettable selectivities of three filter media to oil and water. The selected filters were anthracite, manganese ore and quartz sand particles with a size fraction of +0.9 to 1.2 mm and the wetting liquids were apolar cyclohexane and polar deionized water. At the same time, the effect of filter particle size on the LHR value was also explored. Linear least-square fits for all wetting rates gave regression coefficients of more than 0.9991, confirming the suitability of the experimental method for filter particles and further validating Washburn's theory. The determined LHR values of anthracite, manganese ore and quartz sand are 1.93, 0.75 and 0.69, respectively, which means anthracite is lipophilic while manganese ore and quartz sand are hydrophilic. Moreover, for three selected particle size fractions the LHR values of anthracite particles are always the greatest and that of manganese ore are a little bit greater than quartz sand particles. Therefore, it can be deduced that the wettable differences probably be attributed to the differences of surface chemistries of filter samples. Namely, anthracite surface contains principally organic functional groups composed of carbon and oxygen elements and therefore presents apolar and lipophilic characterization, while manganese ore and quartz sand surfaces have SiO₂ species and make them polar and hydrophilic. This conclusion is approximatively confirmed by the analysis results of X-ray photoelectron spectroscopy (XPS).     

Realistic modelling of the behaviour of fibrous filters through consideration of filter structure

A new model is proposed to describe the effects of structural inhomogeneities in fibrous filters on pressure drop and particle collection. The filter is subdivided into a series of elements with different structural characteristics, defined by local directionally-dependent permeabilities, and the resulting three-dimensional flow field is calculated. Using published relationships, local particle collection is calculated. Spatially nonhomogeneous fibre distribution is shown to play a dominant role. The difference in fibre collection efficiency between a real and a homogeneous filter depends on the dominant mechanism transporting particles to the fibres. In the interception-inertia range, the predictions are verified quantitatively by measurements on industrial filters with characterised structure.     

熔体过滤器清洗工艺优化

阐述了通过增加一道高压水清洗、热水洗以及对泡点试验和过滤芯组装等过程的优化,达到节能降耗,提高清洗效率,延长了过滤器使用周期,消除了此工序给聚酯生产带来的安全隐患。     

Development of a qualitative test method for the cleanability of polymer woven filter media

In this paper a new method for cleaning of filter media is presented, and the cleanability with different textures and surface finishes is compared. With the method described, it is possible to evaluate the quality of the cleaning process. According to the German VDMA standard cleaning test, riboflavin and malt extract are applied as model contaminants for evaluation of the cleaning results. To compare the cleanability of filter media with different properties and geometries the results are adapted to the law of mass transfer and to the Sherwood number, a dimensionless parameter describing the quality of a cleaning process.     

Numerical analysis of flow field in the hot gas filter vessel during the pulse cleaning process

The flow field is simulated for a ceramic filter vessel containing three candle filters which are arranged in the form of an equilateral triangle. Grids generated by GAMBIT are adopted for the simulations. The Reynolds stress model provided by FLUENT code is applied to evaluate gas flow and temperature field in the filter vessel. The temperature profiles in the ceramic candle filter cavity during the pulse cleaning process are analyzed under different operating conditions and for different lengths of candle filter. The evolution of radial velocity in the porous wall of the filters being cleaned and the normal working filters as well as around the filters is discussed. Sharp temperature change takes place in the top of the candle filter which is subject to thermal stress. The phenomenon of temperature increase during the pulse cleaning process has been carefully observed and interpreted based on the effect of gas compression. The simulated results show qualitative agreement with the experimental field observations with the filter vessel.     

三甘醇与高温水蒸气清洗聚酯过滤器的比较

在清洗机理、公用工程消耗、设备、投资、三废排放等方面对三甘醇与高温水蒸气清洗聚酯过滤器的优缺点进行了比较 ,高温水蒸气清洗是一种较经济、可靠的方法     

油浆过滤器滤芯组合清洗技术的研究与应用

通过采用溶剂除油、烘烤除垢、催化转性、酸洗和超声波清洗相结合的清洗工艺和专用药剂配方,有效地清除了油浆过滤器滤芯表面及滤网夹层中的油浆、催化剂粉末和杂质,取得了较好的清洗效果.     

炼油厂原料油过滤器滤芯清洗

原料油过滤器是炼油厂原油二次加工必不可少的设备,但是在使用过程中极易堵塞。采用一般的物理与化学的方法清洗效果不好。通过筛选决定采用高温烘烤、超声波清洗、化学清洗相结合的方法进行清洗,效果很好。     

石油天然气管道中硫垢的化学清洗

用最新研究的 ST 系列硫垢清洗剂,对大庆油田石油三厂天然气热交换器中的硫垢进行化学清洗。清洗结果表明,该清洗剂具有较好的清洗效果,硫垢去除率达96％以上,对管道无任何腐蚀。     

84消毒液除菌过滤后滤芯清洁方法的探讨

对84消毒液除菌过滤后的滤芯,进行3种不同的清洁方法的清洗,探讨最佳的清洁方法。方法对1号滤芯用70℃的注射用水冲洗20分钟,再用20℃的纯化水冲洗5分钟冷却;对2号滤芯用70℃的注射用水冲洗5分钟,再用95%的乙醇冲洗5分钟,然后用20℃的纯化水冲洗5分钟。对3号滤芯用70℃的注射用水冲洗5分钟,连接蠕动泵,用95%的乙醇冲洗5分钟,然后用70℃的注射用水冲洗5分钟,再用20℃的纯化水冲洗5分钟冷却,对1、2、3号清洁方法后滤芯分别进行完整性检测实验。通过1,2号的清洁方法,滤芯不能通过完整性检测实验,而通过3号的清洁方法的滤芯可以通过完整性检测实验。对1号方法未完成完整性检测实验的滤芯再用95%的乙醇冲洗5分钟,用70℃的注射用水对滤芯冲洗5分钟,再用20℃的纯化水冲洗5分钟冷却,其结果能通过完整性检测试验;对方法2,未完成完整性检测实验的滤芯再用70℃的注射用水对滤芯冲洗5分钟,再用20℃的纯化水冲洗5分钟冷却,其结果能通过完整性检测实验。经过验证,通过3号清洁方法对84消毒液除菌过滤后的滤芯进行的清洗是一种有效的清洁方法。     

自动反洗表面过滤器在净化污酸处理中的应用

介绍了重庆华强化肥有限公司2×80 kt/a硫铁矿制酸净化工序技术改造情况。采用"文—电"稀酸洗净化工艺代替"文—间—电"水洗净化工艺,用板式稀酸冷却器代替间冷器,用自动反洗表面过滤器代替澄清池和斜板沉降池,用陶瓷真空过滤机代替压滤机。改造后w（H₂SO₄）约30%的稀酸送入干吸工序和磷铵萃取工序回用,陶瓷真空过滤机产生的w（Fe）>61%滤渣直接外售,每年增加直接经济效益约350万元。     

Jet pulsed filters as chemical gas/solid reactors—Experiment and model prediction

A recently introduced generations filter model [A. Kavouras, G. Krammer, Distributions of age, thickness and gas velocity in the cake of jet pulsed filters—application and validation of a generations filter model, Chem. Eng. Sci. 58 (2003) 223–238] allows one to determine from macroscopic experimental data the distribution of cake thickness versus filter area and in consequence the complete filter behaviour. Based on a simplified assumption this generations filter model is employed in a predictive way to estimate operating points of imperfectly cleaned filters. However, filter behaviour in terms of the fraction of the filter area cleaned when jet pulsed cannot be predicted yet without experimental data. This is due to the variable cleaning properties of the cake, which are dependent on the filter operating parameters.

Combining the predictive filter model and a model for the chemical reactions in the fixed bed of the filter cake [A. Kavouras, B. Breitschaedel, G. Krammer, A. Garea, J.A. Marques, A. Irabien, SO₂ removal in the filter cake of a jet pulsed filter: a combined filter and fixed bed reaction model, Ind. Eng. Chem. Res. 41 (2002) 5459–5469], the filter performance as a gas/solid reactor can also be simulated in a predictive way. It is found that the pressure drop across the filter has a weak influence on filter performance as a gas/solid reactor.     

Aerodynamic behavior of a gas mask canister containing two porous media

This paper discusses the aerodynamic behaviors of a gas mask canister with a complex inner structure and two porous materials in the filter layer and the activated carbon layer. The effects of the distribution and area of holes in the main sieve diaphragm and the thickness of the activated carbon layer on the pressure drop and the flow structure were determined using computational fluid dynamic (CFD) tools. The momentum loss of porous flow calculated by Forchheimer's equation was added to the source term in the momentum equation. Streakline flow visualization was employed to observe gas flow structures within the empty canister and to identify the shortcomings of the prototype canister. Simulation results for the estimated inertial and viscosity parameters in Forchheimer's equation agree closely with experimental values. The porosity of the canister for intake flows of 15-135 L/min causes the flow behavior to transition gradually from linear (viscous effect) to slight non-linear behavior (slight inertia effect). This study uses air age as an index of the time that air resides within the canister to displace the adsorption time of toxic gas. This approach conveniently elucidates overall filter capacity and the positions of dead zones in the activated carbon layer. The simulation results reveal that the channel design of the main sieve diaphragm dominates the aerodynamic behavior of the fluid within the activated carbon layer. Better hole distribution and a larger hole area correspond to a lower pressure drop, a smaller dead zone, and a higher adsorption time. The results in this study provide a valuable reference for designing channels in the main sieve diaphragm, and will be helpful in designing gas mask canisters.