莫莱石—堇青石滤料滤池在生产上的应用

本文对景德镇市黄泥头水厂进行了单层莫－堇滤料滤池和双层莫－堇－煤滤料滤池的生产性试验。试验结果表明：单层莫－堇滤池和双层莫－堇－煤滤池的周期产水量分别是单层砂滤池和双层砂－煤滤池的１．４倍和１．５倍，而且前两种滤池的出水水质优于后两种滤池。     

新型AF滤料处理微污染水的过滤技术

本研究采用新型AF滤料在水厂进行了模型试验和生产性试验。模型试验结果表明：单层AF滤料滤池、双层AF-无烟煤滤料滤池在充氧条件下，滤速为4m／h时，对CODMn的去除率分别为17，4％和21．3％，对氨氮的去除率分别为55％和61％，出水水质均优于国家饮用水标准。生产性试验表明：双层AF-无烟煤滤料滤池的周期产水量是双层石英砂-无烟煤滤料滤池的1．5倍，出水水质前者优于后者，采用双层AF-无烟煤滤料滤池可为供水企业带来显著的经济效益。     

改进的V型滤池中试试验研究

对给水厂普通V型砂滤池进行改造，形成兼有V型滤池优点的煤质活性炭一砂双层复合滤池。利用双层滤料滤池进行中试试验，结果表明，V型双层滤料滤池对沉淀后待滤水浑浊度、NH4^＋-N和CODMn去除率分别达71．72％、68．18％、27．63％，对比相同条件下普通砂滤池，双层滤料滤池对浑浊度去除率下降8.31％，而NH4^＋-N和CODMn去除率则分别上升5．04％和11．25％。活性炭．砂双层复合滤池去浊能力有一定程度下降，去除氨氮、CODMn能力有一定加强。     

滤池滤料改造与节能降耗

该文介绍了通过将单层砂滤池改换成双层滤料滤池后的节约用电及消毒剂的经济效果.     

煤-砂双层滤料滤池运行参数优化试验

强化过滤在饮用水常规处理技术中发挥着重要作用。通过对比国内外煤一砂双层滤料滤池设计参数,设计不同配置滤层的试验滤柱进行优化无烟煤一石英砂双层滤料滤池运行参数研究,可为双层滤料滤池设计运行提供一定的技术支持。试验结果表明,上层无烟煤层厚为600 mm、有效粒径为1.0 mm、K_(80)=1.4,下层石英砂层厚为300 mm、有效粒径为0.5 mm、K_(80)≤2.0的配置下滤柱具有较好的过滤性能。当滤速为12 m/h时,滤池出水浊度控制在0.1 NTU以下,2~5μm颗粒数在3 000/mL以下,过滤周期长达26 h,且可以防止浊度和颗粒数穿透滤池。     

滤池表面助冲技术研究

天津新开河水厂二期工程的过滤系统采用煤砂双层滤料双阀滤池,单池面积为118.4m~2.设计上,滤料铺设厚度为煤30cm,砂50cm,冲洗方式采用反冲洗加旋转管表面助冲。此次表冲试验是在滤池依靠单纯反冲洗运行几个月后,准备停止运行时进行的。当时滤层内积泥较多,煤滤料表面有1厘米厚的黄色覆盖层,泥球清晰可见。本文就表面助冲与传统单纯反冲洗对滤池进行了试     

关于滤料层膨胀公式的探讨

<正> 过滤池是水处理组合体的重要组成部分,其工作的好坏对水质影响甚大。滤池工作周期结束的反冲洗是滤池正常工作中必不可少的过程。如何正确地确定合理的反冲洗过程中的冲洗速度(冲洗强度)和膨胀率,在水处理构筑物的设计和运行管理中是至关重要的。如果膨胀率小,将会使滤料清洗不彻底;而膨胀率过大,又将造成滤料随同污物一起大量流失,从而影响滤池的正常工作。随着水处理技术的不断发展,滤池过滤层的组成也越来越复杂。滤层构造有单层、双层和多层滤料等种类;滤料的种类也很繁多,归纳起来可分为非多孔性滤料(砂、玻     

炭砂滤池与砂滤池处理稳定性微污染地表水对比试验

针对常规净水工艺处理稳定性微污染地表水的不足,进行了炭砂滤池与砂滤池对比试验研究.结果表明.活性炭一石英砂双层滤料具有良好的强化过滤效果,对稳定性微污染地表水中的浊度、CODMn、氨氮、亚硝酸盐氮、UV254的去除率分别可达到95.8%、49.7%、53.3%、52.3%、67.7%,比单层石英砂过滤提高了0.5%、9.9%、13.3%、30.8%、6.2%.增强了滤池的处理负荷,提高了过滤出水的化学安全性.     

吸附-过滤双层滤料滤池的设计与运行

本文介绍一种在普通虹吸滤池的基础上经过简单地改造，而成为具吸附－过滤作用的双层滤料组合滤池的技术而获得明显的效益。     

生物滤池处理微污染水源水试验研究

通过中试试验,探讨了在春季温度较低的情况下,不同滤料介质的生物滤池对于姚江微污染水源水的处理效果。研究表明,双层生物滤料滤池能够有效地去除浊度、有机物、氨氮等污染物质,适合于传统滤池的改造。采用颗粒活性炭-石英砂滤料滤池的综合处理效果优于同类型的沸石-石英砂滤料滤池,通过加入一定量的臭氧(1.50 mg/L)可以进一步提高生物滤池的处理效果。     

Mikroporöse Filtermedien für die Kuchenfiltration

Microporous filters media for cake filtration. Improved knowledge about filtration conditions, capillary phenomena in filter cakes and in filter media, as well as the properties of membranes permit the use of microporous membranes in cake-forming filtration. This allows removal of moisture without passage of gas and yields a particle-free filtrate. Apart from metallic and ceramic membranes, polymeric membranes prove highly suitable as microporous filter media since they permit utilization of the entire range of filter equipment. The present article considers first the fundamentals of cake-forming filtration, then surveys the various membrane systems, and finally discusses process-engineering aspects of filtration with microporous filter media.     

堇青石-莫来石窑具材料的研制

对陶瓷行业常用的几种堇青石－莫来石窑具材料进行了化学成分分析、矿物相分析和显微结构观察,探讨了国内外此类材料在物相组成和结构特征上的差异,并在此基础上研制出了性能优异的堇青石-莫来石窑具材料。     

锂电池正极材料合成用堇青石-莫来石质匣钵研究进展

介绍了锂离子电池正极材料合成用堇青石-莫来石匣钵的开发与应用现状,重点阐述了该材质匣钵面临的主要问题,总结分析了其损毁机制。认为含锂化合物与堇青石、莫来石反应形成的AlLiO 2和LiAlSiO 4导致较大的体积膨胀,因而在热应力及机械力的作用下出现剥落、脱皮导致损毁。同时总结了国内外关于堇青石-莫来石匣钵的改进技术途径,并指出了正极材料合成用匣钵的发展方向。     

Magnesia-phosphate bond for cold-setting cordierite-based refractories

A cold-setting refractory material was developed using the magnesia-phosphate reaction. A cement paste based on alumina, silica fume, magnesia and orthophosphoric acid or monoaluminum phosphate was designed to form cordierite-mullite during heating. This cement paste set at room temperature and MgHPO₄·3H₂O phase (newberyite) was observed, but amorphous phases were predominant. Two exothermic effects were detected during the setting process corresponding to the acid-base reaction of magnesia with phosphates and to the formation of bonding hydrates. At 1100 °C, C-AlPO₄ was formed by reaction of alumina with orthophosphoric acid or monoaluminum phosphate. At 1350 °C, the principal crystalline phases were cordierite and mullite. A refractory concrete with the obtained cement paste and a cordierite-mullite aggregate (scrap refractory material) was prepared. At 1350 °C, this concrete had a thermal expansion coefficient of 1.0×10⁻⁶ °C⁻¹ and a flexural strength of 10 MPa.     

Study on the corrosion resistance of cordierite-mullite and SiC refractories to Li-ion ternary cathode materials

The corrosion reactions of Li-ion ternary cathode material on cordierite-mullite and SiC refractories were studied at 780 °C for 20 h. The XRD and SEM technologies were used to study the corrosion process. The results showed that the interaction between Li₂O and cordierite-mullite material produced a large number of reactants, which led to the failure of cordierite-mullite refractories. For SiC refractories, a small amount of SiO₂ were formed by the SiC oxidation reaction, then the SiO₂ reacted with Li₂O to form lithium silicate compound. Moreover, Li₂O tended to diffuse into the interior of SiC refractory slabs through pores, which avoided the formation of a large amount of reaction products and gave good corrosion resistance to the material without damaging its structure. It has been found that the corrosion resistance of the two materials can be effectively improved by the alumina sol impregnation method.     

Determination of the Fractional Efficiencies of Fibrous Filter Media By Optical In Situ Measurements

ABSTRACT

An experimental setup is introduced to determine the fractional efficiency of fibrous filters. The device includes two optical particle counters for the in situ measurement of the particle flux and size upstream and downstream of a test filter. The simultaneous measurement in the raw and clean gas by a counting method allows a rapid determination of the fractional efficiencies of various filter media within a few minutes. In the first experiments performed with different aerosols (latex spheres, bacterial aerosol, limestone dust) the apparatus proved to be a reliable instrument for the investigation of the collection behaviour of fibrous filters influenced by various parameters.

The fractional efficiency yields more information about the filter performance, i.e., respirable fraction, collection minimum, particle bouncing off etc., than the total collection efficiency. Thus it is possible to compare different filter media of the same or different filter class and determine their optimum operational conditions.     

水清洗对空气净化材料过滤性能的影响

用于空气净化的材料一般为一次性使用,但有的应用场所需要对其进行反复水清洗多次使用。通过实验手段,研究常规涤纶纤维层滤料,在荷尘、清洗、烘干、荷尘等多次反复中其过滤效率、阻力、容尘量的变化情况。实验结果表明,清洗对滤料的过滤效率、阻力和容尘量没有明显的影响,滤料可以通过水清洗的方式反复使用。     

Novel cordierite-acicular mullite composite for diesel particulate filters

Cordierite-acicular mullite composites containing 0, 25, 50, 75 and 100 wt% of mullite were fabricated from waste MoSi₂ and commercial powders of Al₂O₃ and spinel (MgAl₂O₄). Careful oxidation of pulverised waste MoSi₂ rendered a precursor mixture of MoO₃ and amorphous SiO₂, which served as pore forming agent and SiO₂ source, respectively. Evaporation of MoO₃ at ～750 °C allowed production of highly porous cordierite-mullite ceramic composite after sintering in air at 1350 °C for 4 h. The combination of equiaxed cordierite grains and elongated (prism-like) mullite grains, resulted in unique microstructure with open porosity between 53.3 and 55.6 vol% which makes the obtained composite convenient for application as diesel particulate filter material. The presence of mullite affected four key thermo-mechanical properties which determine the thermal shock resistance of cordierite-mullite composite. The best thermal shock resistance was measured in composite containing 75 wt% of mullite. It was a result of improved thermal conductivity (1.081 W/mK) and bending strength (3.62 MPa) and relatively low values of coefficient of thermal expansion (3.8 × 10^?6 K^?1) and elastic modulus (2.27 GPa).     

The influence of conditioning and regeneration on the separation behaviour of rigid surface filters for the separation of particles from gases

Rigid ceramic filter media can be used for the separation of particles from gas streams at elevated temperatures. In order to characterize comparatively the separation behaviour of differently structured filter media over a multitude of filtration cycles, experiments were performed in a filter test rig. The filter test rig used is built in accordance with VDI guideline 3926 and equipped with a special type of optical particle counter, which has the advantage of measuring both the particle size and the particle concentration simultaneously and in situ on the clean gas side.

It is demonstrated that by far largest share of the particles reaches the clean gas as a result of the filter regeneration process. During the subsequent formation of the dust cake, the particle penetration is almost zero. The regeneration parameters, actually in essence only the tank pressure, possess the decisive influence on the separation behaviour. In the course of a filtration experiment, the number of particles reaching the clean gas reduces with the increasing number of filtration cycles due to the filter conditioning. The particles arriving in the clean gas during regeneration are extremely fine. The mean particle size is almost entirely independent of the regeneration conditions and the filter cycle number. The fine particulate emissions measured here are an anthropogenic source of particulate matter in ambient air. They have to be considered as relevant with respect to the new standards of ambient air quality (PM 10 and PM 2.5).

It is shown that membrane-coated ceramic filter media at identical operating conditions exhibit, as expected, a better separation and regeneration behaviour than fibrous ceramic, open-pored filter media. However, the advantages are at the expense of a 10 times higher pressure loss, which is essentially attributed to the membrane layer.