机织滤布的透水性能研究

对不同材质、不同纤维类型和不同编织方法的滤布的透水性能进行了研究,分析了诸因素对滤布透水性能的影响,研究结果对今后实际作业中滤布选型有一定的参考价值。     

透水混凝土透水系数与孔隙结构的相关性研究

对透水混凝土的有效孔隙重新进行了定义,并提出了有效孔隙率的测试方法.在此基础上,对与多孔介质透水系数相关的方程进行综述,通过Ergun修正的雷诺数Re'对透水混凝土中水的流动状态作出判断,选择Kozeny-Carman方程研究了透水系数与有效孔隙率和平均孔径之间的相关性.结果表明:随着全孔隙率的提升,有效孔隙率急剧上升;在只考虑有效孔隙率对透水系数的影响时,本研究应用Kozeny-Carman方程能够很好地表达透水系数与有效孔隙率之间的关系;但同时考虑有效孔隙率和平均孔径对透水系数的影响时,无法用Kozeny-Carman方程复现透水系数.     

粉煤灰透水混凝土孔隙率和渗透系数的试验研究

粉煤灰等量取代水泥进行透水混凝土强度的改性有明显的效果,然而随着强度的提高,透水混凝土的孔隙率和渗透系数也有明显降低。通过测定不同掺量粉煤灰取代水泥改性透水混凝土的孔隙率和渗透系数并进行对比,研究粉煤灰透水混凝土内部结构的变化,分析不同集料粒径透水混凝土粉煤灰掺量对孔隙率和渗透系数的影响。结果表明,采用体积法测定透水混凝土的孔隙率,两种集料透水混凝土的孔隙率基本都保持在15%以上;透水混凝土渗透性能较好,过水断面流水速度大,上下水头变化较大,故建议采用降水头法测定其渗透系数;粉煤灰的掺加对小粒径透水混凝土孔隙堵塞较大粒径透水混凝土严重,渗透系数下降明显。     

高效过滤技术研究与新进展

本文系统介绍了国内外在提高过滤分离速率、过滤分离精度及过滤设备运行效率等方面的研究与新进展，并作了简要综合评述，最后对新型高效过滤技术的研究进行了展望。     

粗骨料对透水混凝土性能的影响研究

试验研究了粗骨料品种、粗骨料粒径、胶骨比等对透水混凝土力学性能和透水性能的影响,结果表明:采用天然骨料配制的透水混凝土的各项性能均优于采用再生骨料配制的透水混凝土;对于同一来源的粗骨料,骨料粒径越大,配制的透水混凝土透水性能越好,力学性能则略有降低;相同品质和粒径的再生骨料配制的透水混凝土,随胶骨比增加,混凝土透水性能逐渐降低,力学性能却呈增加趋势。     

净水功能型透水混凝土的组成设计研究

为净化雨水和补充地下水,设计了一类净水功能型偏高岭土基地聚合物透水混凝土。通过研究壳聚糖掺量、碱激发剂模数与碱当量对偏高岭土基地聚合物浆体力学、吸附特性的影响,制备了一种可用于透水混凝土的高吸附性浆体材料。基于此,进一步探讨了透水混凝土骨料堆积孔隙率、浆集比(P/A)等体积结构参数对其净水、透水与力学性能的影响。结果表明:随着壳聚糖掺量的增加,偏高岭土基地聚合物的强度呈先提高后降低的趋势,Pb²⁺的吸附量呈增大趋势;随着骨料堆积孔隙率的增大,透水混凝土的力学和净水性能均减弱,透水性增强;随着浆集比的增大,透水混凝土力学与净水性能增大,透水性减小。最终设计出净水、透水与力学性能协调的透水混凝土,其28 d抗压强度、透水系数和Pb²⁺去除率分别为20.1 MPa、0.67 cm/s和90.5%。     

非织造过滤介质孔径及截留性能的研究

对应用于液固分离和气固分离的非织造过滤介质的孔径和截留性能测试方法做了研究,指出采用气体流量法进行孔径性能测试,可同时得到非织造过滤介质的最大孔径、平均孔径及孔径分布,全面表征了其孔径性能;并对用于液固和气固分离2个不同领域的非织造过滤介质采用不同的方法做了截留性能测试。同时,对比非织造过滤介质的孔径和截留性能,对二者之间的关联做了探索,为实际工业过程中非织造过滤介质的选用和评价提供了指导。     

提纯木聚糖碱抽提液的超滤模式

研究了提纯木聚糖碱抽提液的3种超滤模式对膜透过速率、盐去除率、糖截留率、超滤时间的影响。物料直接进行间歇式超滤,脱盐效果差,膜透过速率低,浓差极化现象严重。当物料先离心,木聚糖沉淀用水洗至无盐,所有离心清液合并后再间歇超滤时,生产工艺复杂,膜污染未能得到有效改善,而且增大了处理量和延长了超滤时间。理想的超滤模式是将物料不离心、连续超滤并保持初始体积,该模式膜平均透过速率最高且具有较好的稳定状态,在滤出7.70 L清液时,盐去除率高达96.23％,处理时间仅需215.7 min。     

Influence of inherent particle characteristics on hopper flow rate

The inherent factors influencing the shear strength of particulate materials are also believed to influence the flow rate through a hopper. These inherent particle characteristics include particle size, particle-size distribution, particle shape, angularity, hardness, and surface roughness. To determine the effect of inherent particle characteristics on flow rate and pluviated void ratio, a wide range of materials were tested. These materials ranged from manufactured sands and glass beads to natural sands. Determination of particle size, particle-size distribution, and hardness was achieved by conducting conventional tests such as sieve analyses and specific gravity tests. Quantification of the shape and angularity parameter is more difficult due to the nonavailability of any standard techniques. To achieve the objective of quantifying shape and angularity, a new technique was developed utilizing the image analyzer. Two shape parameters, namely, Shape Factor and Angularity Factor, were determined for various materials. Shape and Angularity Factors were correlated with flow rate as well as the pluviated void ratio. Overall, the results indicate that as shape and angularity of particles increase, the flow rate decreases, and pluviated void ratio increase. A good correlation between drained shear strength properties and the flow rates measured in the cone was also found to exist. Therefore, index tests such as flow rate through a flow cone (hopper) can be used to estimate the drained monotonic strength of particulate materials.     

基于模糊规则的多模型固相质量流量软测量

针对静电传感器无法给出颗粒质量流量绝对值以及多相流流动形态和结构变化影响传感器输出等问题,提出了一种基于分解合成的多模型加权平均的固相质量流量非线性软测量模型。在高压密相气力输送系统上,通过静电传感器获得大量试验数据,提取信号特征,利用模糊聚类算法将输入数据进行空间分区, 每一区间上用径向基函数（RBF）神经网络辨识出一个子模型, 再利用模糊推理将各子模型输出加权求和得到颗粒质量流量的估计值。该模型减小了流型对测量结果的影响,提高了测量精度。     

Effects of particle concentration and size on the dissipation rate and turbulent kinetic energy of oil

The presence of particles in oil can change the quasi-sequence structure of the turbulent flow of the oil, and it is extremely important to explore the turbulent energy dissipation rate of the particulate-containing oil and ensure the safe and stable operation of the oil-using equipment. Thus, the flow field of the oil containing particles in the pipeline was experimentally studied by a particle image velocimeter (PIV); the turbulent kinetic energy of the oil was calculated using the transient velocity vector field measured by the PIV; and the dissipation rate distribution was calculated using the large eddy PIV method. The influence of different particle sizes and particle concentrations on the normal distribution of the turbulent kinetic energy and dissipation rate was analyzed. The results show that the distribution of the turbulent kinetic energy in the normal direction is non-unidirectional and in a parabolic shape. The 25 μm particle size has a great influence on the turbulence kinetic energy and the dissipation rate of the oil; with increasing particle concentration, the flow field distribution of the turbulent kinetic energy increases in the region near the wall, and gradually decreases in the central region. The turbulent kinetic energy distribution of the oil is in the shape of a quasi-cosine; the flow field of the dissipation rate is larger in the near-wall region and the central region and shows an inverted ‘W’ shape. This provides a theoretical basis for improving the efficiency of oil transportation, discussing the monitoring of particulate matter in oil, and reducing oil pollution.     

Counting and particle transmission efficiency of the aerodynamic particle sizer

The aerodynamic particle sizer (APS) measures the size distributions of particles with aerodynamic diameter between 0.5 and in real time. To provide accurate size distributions, the APS must measure both particle size and concentration correctly. The objective of this study was to characterize the counting efficiency of the APS as a function of particle size (0.8–), particle type (liquid or solid), and APS model number (3310 vs. 3321). For solid particles, counting efficiencies ranged between 85% and 99%. For liquid droplets, counting efficiencies progressively declined from 75% at 0.8-μm drops to 25% for 10-μm drops. Fluorometric wash tests indicated that transmission losses occur when larger droplets impact on the instrument's inner nozzle. However, transmission losses did not account entirely for the reduced droplet counting efficiencies, indicating that additional losses may have occurred downstream of the inner nozzle. Between instrument comparisons revealed that although multiple APSs report similar number concentrations, small deviations in particle sizing can produce substantial errors when number concentrations are converted to mass concentrations.     

大粒径硅溶胶粒径增长及其控制工艺的研究

大粒径硅溶胶在涂料、化学机械抛光、催化剂载体等工业领域中都有着极其广泛的应用。在添加适量催化剂的条件下,采用单质硅粉氧化法制备了大粒径溶胶。重点介绍了大粒径硅溶胶的分类、性质及应用,通过研究不同条件下大粒径硅溶胶的粒径增长过程分析了大粒径硅溶胶制备过程中的粒径增长机理。在添加阴离子表面活性剂的条件下,采用浓缩蒸馏实验研究了大粒径硅溶胶粒径增长与其浓度的关系,结果表明：随着大粒径硅溶胶浓度的增大,大粒径硅溶胶的粒径呈先减小后增大的趋势。最后提出了制备大粒径硅溶胶的粒径控制工艺。     

Flame spray drying: Droplet and particle flow dynamics

ABSTRACT

The work presents the fundamental research of dispersed phase flow during flame spray drying. Particle dynamics analysis and laser Doppler anemometry technique were applied to determine particle size distribution and particle velocity distribution. Results of the study showed that stable combustion and longer length of the flame were observed for coarse spray (large droplets, low atomization pressure, small spraying angle, and low concentration of droplets in spray). Particle residence time in the combustion zone is the main factor affecting the increase in particle diameters due to puffing. Complex flow dynamics of dispersed phase observed at the outward regions of the flame in recirculation zones results in the formation of particle agglomerates.     

隔板式内循环流化床颗粒循环速率实验与模型

在不同操作参数及结构参数下对隔板式内循环流化床的颗粒内循环速率进行了实验研究,研究了高速区和低速区的流化速度、静床层高度、隔板间隙等参数对颗粒内循环流动的影响。结果表明这4个参数对颗粒内循环速率都有显著的影响,当其他3个参数确定时,随着其中一个参数的增加,颗粒内循环速率均呈现先增加后减小的趋势,这一结果表明,颗粒内循环过程是多种操作和结构参数的非线性复杂系统。为预测颗粒内循环速率,修正了La Nauze 模型,该模型无须提供压降参数即可计算颗粒内循环速率,对于多种颗粒,其计算结果和实验相差在23%之内。     

成庄矿选煤厂流量限制点的分析及改造

分析了影响成庄矿选煤厂生产效率的因素,提出实现选煤厂高效生产的关键在于从系统流量的最大化入手,找出限制系统流量的关键设备并进行改造。依据网络最大流理论,通过对选煤厂生产系统设备网络的分析,得到了成庄矿选煤厂的流量限制点,即主输送带和307,308,309,310筛分设备。通过更换3套900 kW的驱动装置及配套变频器,选用型号YK3052的307,308筛子,选用型号2ZK3052的309,310筛子等措施,提升了主井胶带输送机的生产能力和筛子的处理能力。最后对选煤厂改造效果进行了分析,成庄矿选煤厂改造完成后,网络最大流可达1500 t/h,生产能力由原先的400万t/a提高至目前的804万t/a,节电5386.8万kWh/a。在不增加其他设备投资的情况下,选煤厂发挥了设备的最大潜能,为其它选煤厂的扩能改造提供了理论基础。     

旋风收尘器的收尘效率和生料粒度分布关系

旋风收尘器所分离的固相颗粒大小对分离效率的影响非常显著,通常情况下只对10μm以上的颗粒保持很高的分离效率,对直径小于6μm的细颗粒的分级效率相对较低。本文分析了不同公司的生料粒度分布情况,通过计算生料的粒级效率、中位粒径,并对C1旋风筒技改后的生产线收尘效率进行对比,分析旋风筒收尘器与生料粒度的关系。     

Gasification of biomass wastes in an entrained flow gasifier: Effect of the particle size and the residence time

Experimental tests in an entrained flow gasifier have been carried out in order to evaluate the effect of the biomass particle size and the space residence time on the gasifier performance and the producer gas quality. Three types of biomass fuels (grapevine pruning and sawdust wastes, and marc of grape) and a fossil fuel (a coal-coke blend) have been tested. The results obtained show that a reduction in the fuel particle size leads to a significant improvement in the gasification parameters. The thermochemical characterisation of the resulting char-ash residue shows a sharp increase in the fuel conversion for particles below 1 mm diameter, which could be adequate to be used in conventional entrained flow gasifiers. Significant differences in the thermochemical behaviour of the biomass fuels and the coal-coke blend have been found, especially in the evolution of the H₂/CO ratio with the space time, mainly due to the catalytic effect of the coal-coke ash. The reaction temperature and the space time have a significant effect on the H₂/CO ratio (the relative importance of each of these parameters depending on the temperature), this value being independent of the fuel particle size.