水电站砂石加工系统生产废水理工艺试验研究

针对现有水电站砂石加工系统产生的高悬浮物废水的处理工艺存在的排泥系统易堵、沉渣脱水困难的问 题,通过对砂石加工废水中悬浮物的沉降性能、粒径分布和沉渣的脱水性能的相关分析,提出了组合式沉淀工艺处理砂石加工废水.结果表明,成功实现粗细颗粒的分开沉淀,保证一号沉淀池粗颗粒沉渣在90 min内外排是解决沉渣淤池堵管的关键.当控制1、2号沉淀池的总水力停留时间在30 min左右,可基本实现粗颗粒的前端分离,SS去除率可达60％以上,后端经过3号沉淀池的强化絮凝沉淀,出水SS基本可达到污水综合排放标准中的一类排放标准,最终可达到废水处理“零排放”的目的.     

Numerical modelling of the carrier gas phase in a laboratory-scale coal classifier model

The pneumatic transport of fine ideally combustible coal dust to the burner furnace is an important process in coal fired power plants. The strongly swirling air phase responsible for the particle separation and transport in a coal pulverising mill was characterised experimentally and numerically. Measurements of the swirl velocity component were taken in a scaled laboratory model of the device and compared to CFD model. In particular, an evaluation of the turbulence models used to describe the flow was performed. The modified isotropic k-epsilon turbulence models (RNG k-ε and Realizable k-ε) were compared to the anisotropic Reynolds stress model (RSM) and their ability to predict the bulk flow structure present in the classifier was assessed. The experiments showed that the swirling flow structure, responsible for coarse-fine particle classification, has several flow regimes which are governed by the areas it is bounded by. The numerical model predictions generally corroborate the results. However, a distinction in performance between the three models can be made based on accuracy, solution generation time and numerical stability. The RSM model predicted both the trends and magnitude the most accurately when compared to the isotropic models. However, the Realizable k-epsilon model, with its relatively low solution generation time, shows potential when using CFD as a classifier design optimization tool. The investigation has given some insight on single phase classifier flow and suggests a design improvement based on the results.     

铁水罐低成本防粘渣喷涂料的研制与应用

以鱼雷罐用后Al2O3-SiC-C砖的再生料(Al2O3质量分数≥70%,粒度为3~1、1~0.297、≤0.297 mm)为主要原料,以矾土水泥、软质黏土和α-Al2O3微粉为复合结合剂,以硅酸盐水泥为促凝剂,以用后硅酸铝纤维再生料(长度3~8 mm)为防爆剂,研制了成本低,防粘渣效果好,并且易于清渣的防粘渣喷涂料。在高铝砖砌筑的脱硫铁水罐上使用,寿命由原来的550次延长到800次以上。     

正旺铁矿声发射监测点的优化布置

利用有限元分析计算软件建立了正旺铁矿的三维数值模型并计算了采场的整体稳定性,根据计算结果找出-560 m水平由于应力集中效应而产生的较大的应力范围.然后结合正旺铁矿-560m水平中段图,标示出应力较大点位置,在此基础上优化声发射监测点的布置,从而为采空区的加固和声发射监测提供较准确的理论依据,为矿山的安全生产提供保障,...     

特种表面活性剂和功能性表面活性剂(Ⅻ)——环糊精及其衍生物的制备与性能

简单介绍了常用的α-,β-和γ-环糊精(CD)的结构和性能,重点综述了环糊精各类衍生物(包括醚类、酯类、去氧类和聚合物类等,其中聚合物类包括交联型、线形和固载化3种类型)和包结复合物的制备方法及性能,并对其今后的发展进行了展望。     

基于S变换和径向基神经网络的暂态电能质量扰动识别

提出一种基于S变换和径向基神经网络的暂态电能质量扰动识别的方法。该方法首先用S变换对暂态电能质量扰动波形进行预处理．使用统计的方法提取了5个相关特征量,然后用径向基神经网络对提取的特征量样本进行分类。仿真结果表明,该方案正确率高,抗噪声能力强,训练样本少,响应快速．     

基于BP神经网络的多光谱空间表示方法研究(英文)

多光谱成像技术通过增加颜色通道的维数,克服了传统颜色复制方式在同色异谱方面的缺陷,成功的实现了基于光谱的颜色复制。然而,由于其颜色信息维数较高,此方法在提高色度精度的同时引入了较大的计算及存储压力。为此,最常用的方法就是通过特定的光谱分组度量对光谱数据进行分组,并利用每组光谱数据集中的主成分向量来对各个光谱曲线进行线性表示,从而实现数据的降维处理。本研究提出了一种全新的,基于主波长分组及BP神经网络寻址的光谱空间表示方法,并通过对具体光谱颜色数据集的向量表示,证明此方法在光谱颜色表达的方面的准确性。     

Particle motion and separation in a laminar tube flow with downstream enlargement

Particle classification becomes difficult when the difference in density between particle and fluid is low or negligible and the fluid is viscous. For such applications, a process capable of separating the particles according to their size is needed. Such applications are, e.g. found in biological systems for cell separation or in the removal of gel particles from polymer melts. Particle transport in laminar tube flows at low but non zero Reynolds numbers leads to accumulation of large particles near the tube center and forms a particle free zone near the wall. Small particles find their position on their equilibrium radius. Downstream widening of the flow enhances segregation between large and small particles. Large particles can be collected in a centered collector tube downstream, whereas small particles follow their streamlines around the collector tube and can be removed with the remaining flow. The said particle migration is observed when the ratio of particle to tube diameter is 0.2<d/D<0.51 and the tube Reynolds number is in between 0.2<Re<40. CFD simulations reveal the shape of the streamlines in the downstream enlargement with different tube Reynolds number. The efficiency of the classification process is characterized. Particles need a sufficient transportation length in the tube for proper demixing. This effect is analyzed by a laser sheet illuminated system within an acrylic glass tube.     

PCB分级产物热解动力学研究

以粗破碎后的PCB为例,利用分级机对其进行分级,研究PCB中铜的分布与分级的关系,并对分级后产物进行热解动力学研究.分级结果表明,分级产物主要存在于分级轮转速为290 r/min的除尘器中,为55.53wt%;铜主要富集于870 r/min除尘器中,为61.83wt%.TG-DTG分析表明:除870 r/min除尘器产...     

Beurteilungskriterien für sicherheitstechnische Prüfungen

Methods are presented which enable one to assess and compare the hazard potentials of different technical installations without the necessity of a detailed technical plant analysis. The basis is the energy content of the installation. In the case that energies with different impact mechanisms, e.g., pressure and heat, are to be compared, the probit method is used. In addition, the expected frequency of occurrence is included in the assessment. This is an approach which is already used in neighboring countries. It is foreseeable that it will gain importance in Germany as well. In the case of elevators the predator‐prey model is used to analyze the time series of accidents. The influence of errors in inspection and maintenance is put into evidence by comparison with the SIL classification.