Improved design of dust test chamber for uniform distribution of dust sedimentation rate

Soiling problems are always encountered for equipment installed in outdoor environments, such as headlamps of automobiles, air conditioners, solar collectors, and so on. How to prevent soiling problems on this equipment is one of the challenges for the design of their external layouts. Thus, evaluations of the dust sedimentation quantities on the surfaces of such equipment are necessary. Outdoor testing is usually straightforward but it takes a long time to experience various environmental parameters, such as dust-laden air, wind speed, wind direction, and so on. Indoor tests, performed in a dust test chamber, are instruments for controlling various environmental parameters independently. The conventional design for a dust test chamber is aimed at providing for a test under extreme environmental conditions. The uniformity of dust sedimentation rate within the chamber is not rigorously controlled. Nevertheless, some applications such as the effect of dust sedimentation on the glazing of solar collector require uniform distribution of dustfall in the test chamber for the indoor (laboratory) test. An improved design for a conventional dust test chamber is proposed. Performance tests done with the remodeled dust test chamber based on the improved design show that the normalized standard deviation of the dustfall concentration can be controlled within 2.41% ± 1.29%.     

Preparation of fused silica membrane with high performance for high temperature gas filtration by sealing and spray coating

In order to improve the gas permeability and thermal shock resistance of the ceramic membranes applied in high temperature gas-solid separation techniques, fused silica and graphite particles were used as the primary raw material and pore-former agent, and the spray coating based-on PVA sealing was applied to prepare the separation membrane. These approaches remarkably decreases filtration resistance by increasing support permeability and reducing the intrusion of ceramic membrane forming particles into the support as well as the thickness of the membrane. The fabricated membrane had an average pore diameter of 9.85?μm and a gas permeability value of 8.2?×?10⁴?m³/(m² h bar), its dust removal efficiency reached 98.6%.     

排尘口直径对旋风分离器壁面磨损影响的数值模拟

基于计算流体动力学(Computational fluid dynamic,CFD)的数值模拟方法,在FLUENT软件平台上,应用雷诺应力模型、离散相模型和磨损值计算模型系统地研究排尘口直径对旋风分离器壁面磨损的影响。计算结果表明,旋风分离器壁面磨损的整体变化趋势不随排尘口直径的改变而变化,都呈现局部磨损的形态。排尘口直径减小,环形空间壁面磨损值保持不变,分离空间壁面磨损值有不同程度的增加,在锥体末端附近增加幅度最大,而这种变化主要是由于排尘口直径变化后分离器内部流动结构的变化引起的。分离空间锥体末端附近壁面的严重磨损主要受气固两相的旋转速度、颗粒浓度、旋进涡核和颗粒受力情况的影响。通过研究揭示合理地进行结构设计在减少磨损中的重要作用,为旋风分离器壁面的防磨提供数值试验方法和依据。     

炼铁厂出铁口烟尘综合利用的研究

本文分析了炼铁厂出铁口烟尘的性质,并用选矿方法对烟尘进行提纯,通过重选、磁选、浮选的试验研究,结果表明;“分级一磁选”效果最好,可获得铁品位为68．78％的超级铁精矿,回收率为66．22％;另一铁精矿品位为57．93％,回收率为32．86％;尾矿铁损失率仅为0．92％。文章还对后续深加工提出了具体建议。     

Consideration of the stress dependence of the bulk density in silo storage of dusts from dry off-gas cleaning

In this study the influence of the consolidation stress on the bulk density of dusts separated from the off-gas of a broad variety of industrial processes was investigated. With the exception of very small values of the stress this dependence can be approximated very well by a simple function. One coefficient in this function correlates very well with the bulk density measured according to EN ISO 60, while the other coefficient shows a good correlation with a function, combining several dust properties. Using this approximation function equations for the vertical stress and bulk density in the shaft of a cylindrical silo as a function of the distance from the surface were derived. The results for the vertical stress and the mass of the bulk obtained with these equations were compared with those acquired on the basis of Janssen’s equation assuming constant bulk density according to EN ISO 60 and a constant average bulk density. Up to a certain distance from the surface of the bulk the values for the stress and for the mass were between the results obtained by the two variants with constant bulk density, whereas for greater distances the resulting values were higher.     

Synthesis and performance measurement of a modified polymer dust suppressant

In order to address the problem of dust pollution formed during coal production processes, we chemically modified sodium alginate (SA), an environmentally friendly macromolecule polymer, to achieve a grafted product. IR and NMR were employed to investigate the structure of the grafted products. A contact angle experiment was used to select surfactants with good wettability, which were subsequently combined with the water-retaining agent CMS and SAE–XG–3, to fabricate an environmentally friendly dust suppressant. A high–resolution scanning electron microscope (SEM) was used to analyze the morphology of the cured film that formed on the surface of coal dust. A spraying test was performed to measure the dust suppressant’s performance. The experimental results demonstrated that the environmentally friendly dust suppressant possessed good water retention, viscosity, and wettability, and could achieve suitable dust bonding and settlement performance. In addition, the newly developed dust suppressant is environmentally friendly and has economic benefits.     

水压爆破拆除除尘器基座

利用水压爆破技术对钢筋混凝土除尘器基础进行爆破拆除。论述了水压爆破药量的计算、药包布置、药包入水深度与安放、炸药的防水处理、爆破网路及起爆方式、安全防护等技术措施。经过精心施工,取得了预期的爆破效果。     

电荷对粉尘和病原体团聚影响的数学模型研究

由于封闭畜禽舍内聚集了大量的粉尘和病原体,将影响到动物和饲养人员的呼吸道健康,因此迫切需要研究去除粉尘和病原体的方法。以粉尘和病原体的结合体为研究对象,利用蒙特卡罗法及相关概率模型,研究电荷对粉尘和病原体团聚影响。通过研究粉尘和电荷间的附着模型,确定其附着受粒子半径、电荷情况、风速等因素影响;之后,进一步构建粉尘、病原体间以及病原体、电荷间的附着模型。结合数值化运算设定边界条件,得出三者间的结合率可达到15%。粉尘、病原体与电荷相互之间模型的建立能有效的了解到畜禽舍除尘的方法,提高除尘效率,并为高压静电除尘的推广和应用提供了理论基础。     

袋式除尘器在水泥工业中的应用状况及研究进展

从袋式除尘器的滤料、清灰方式、清灰状态等几个方面论述了袋式除尘器的发展及应用情况,并且涉及实际应用中出现的问题及解决方法以及袋式除尘器最近几年发展的新技术。     

塑料厂除尘系统的设计分析

除尘系统是捕集、输送、净化含尘气体直至干净气体排放的整个系统,它由集气吸尘罩、除尘管路、除尘设备、除尘风机等组成。提出了除尘系统的设计原则和计算方法,为正确选择、合理配置除尘系统提供了设计依据