改性塑料规整填料的流体力学和传质性能研究

主要研究了不同比表面积和开孔率塑料规整填料表面处理前后的流体力学和传质性能。结果表明：经过表面改性后,传质性能可提高约20%～35%,开孔填料经表面改性后阻力不会增加,并且在低喷淋密度时传质效率提高显著。     

规整填料表面点传质的可视化研究

采用显色化学反应的流体可视化方法研究规整填料表面上的点传质效果。并且用高精度彩色扫描仪进行后处理,把颜色值转化为数字值。通过风洞的标定特性来建立数字值和点传质量之间的关系,进而得到填料表面的点传质系数。由填料表面点传质系数的三维分布图,可清晰地看到在每两片填料交叉形成的任一传质单元当中,存在3个传质高峰。     

CFD Study on the Local Mass Transfer Efficiency in the Gas Phase of Structured Packing

Visualization of local mass transfer coefficients over the dry surface of corrugated‐sheet structured packing is essential for optimizing the existing geometry of structured packing and for improving mass transfer efficiency to develop new structured packing. The local flow patterns between packing sheets and the gas‐phase mass transfer coefficient at each point over the surface are illustrated by employing a wall‐surface reaction model. Different turbulence models are utilized, i.e., a standard κ‐? model and three different low‐Re‐κ‐? models. The numerical calculation results with the Lam‐Bremhorst low‐Re‐κ‐? turbulence model is found to agree well with experimental data. There are three similar regions with enhanced mass transfer efficiency in each mass transfer unit cell of structured packing.     

规整填料上传质现象的CFD模拟研究综述

归纳了规整填料板上传质现象的CFD模型,总结了规整填料板上整场浓度分布规律以及物性参数、操作参数及填料几何结构等因素对传质速率的影响。在此基础上归纳出对传质与流动之间定量关系的探究以及新型填料板的开发是未来的研究重点。     

CFD‐assisted Characterization and Optimization of the Structured Mass Transfer Packing QVF DURAPACK®

The glass packing QVF DURAPACK® was developed to use the advantages of structured mass transfer packings, especially when handling corrosive media. To match up with the latest developments for sheet metal packings, further optimization for liquid‐liquid separation processes was performed for the QVF DURAPACK®. The complex geometry of structured packings and the wall thickness of glass sheets complicate the numerical investigations. The modeling strategy is presented, and the limitations of CFD tools are given. The experimental and numerical results show similar trends as known for perforated metal structures. The extraction efficiency of the packing prototype could also be reproduced with the column design tool LLECMOD.     

高效规整填料塔技术在苯酐精制过程中的应用

介绍了国内苯酐精制新工艺和高效规整填料塔技术。实际应用结果表明新工艺比旧有技术和设备提高了产品质量和收率 ,处理能力也大幅提高 ,能耗明显下降。     

A Shortcut Method for Estimating the HETP of Structured Packed Distillation Columns at Elevated Pressure

A shortcut model is developed for predicting the HETP of a structured packed distillation column operating at elevated pressure. The proposed model incorporates the geometrical parameters of the packing, physical properties of the vapor and liquid phases, and the hydrodynamics of the two‐phase flow. The proposed model is tested and validated by comparing the predicted results with the present experimental data and some published HETP data. The results show that the proposed model can predict the experimental data with a deviation smaller than 20 %.     

Efficiency of a Gas‐Liquid Contactor for the Oxygenation of Activated Sludge: Assessment of Mass Transfer Coefficient

The aim of this work is to investigate a co‐current air‐liquid downward flow bubble column with air entrainment by liquid injection nozzle in order to use it as an aerator in activated sludge treatment plants. The study concerns the determination of mass transfer efficiency by measuring the mass transfer coefficient, k_La, both in clean water and in activated sludge. In clean water, this parameter is determined by three methods, i.e., gassing out method, absorption with chemical reaction and off‐gas method. In activated sludge medium, k_La values are measured by two methods, i.e., sludge reoxygenation and the hydrogen‐peroxide method. The values of k_La obtained in clean water are compared to those obtained in sludge, enabling the assessment of the α factor, i.e., ratio of oxygen transfer coefficient sludge/clean water. The results are in good agreement with those reported previously in the literature.     

前处理方法对微量沙尘气溶胶样品矿物实验结果的影响

为了探讨前处理方法对微量沙尘气溶胶样品矿物分析结果的影响,对2002年春季甘肃敦煌采集的3次沙尘暴样品分别进行了5次重复前处理和矿物分析实验研究.X射线衍射分析显示,8种沙尘气溶胶组成矿物的5次实验结果的标准偏差相对于平均值均较小.同时计算的石英、斜长石、方解石、伊利石、绿泥石和高岭石等沙尘气溶胶的主要组成矿物的相对标准偏差均小于10%,表明前处理方法对微量沙尘气溶胶样品的矿物分析结果影响较小.     

Determination of the Henry's Coefficient and Mass Transfer for Ozone in a Bubble Column at Different pH Values of Water

In this study, the ozone gas-liquid mass transfer into water in a bubble column was investigated for different pH values. The ozone volumetric mass transfer coefficient and the Henry's coefficient were determined simultaneously by parameter estimation using a nonlinear optimization method. A sensitivity analysis was conducted to obtain information on the reliability and identifiability of the estimated parameters. A minor dependence of the Henry's law constant on pH was detected at the pH range 4 to 9.     

Moldflow在化妆品粉盒底盖注塑模设计浇口位置选择中的应用与研究

化妆品粉盒底盖,产品要求表面光滑手感好;化妆品底壳要与上盖的卡扣等处配合,且卡扣处为薄壁且与侧壁垂直使填充可能会有阻力但又要求有较强的力学性能。因此浇口位置的选择决定了塑件的外观质量、卡扣销孔处的填充好坏、尺寸收缩率大小等问题,是该塑件模具设计的的关键问题之一。传统的模具设计主要依靠设计人员的直觉和经验,需要经过反复的调试与修模才能正式投入生产;利用Moldflow软件在模具设计加工之前,对浇口位置的选择进行模拟分析,找出可能出现的缺陷,有利于为注射模具的设计和加工提供指导,以缩短生产周期,从而减少对设计者经验的依赖。     

PLS回归软测量方法在催化重整稳定油组分估计中的应用

提出扰动分类法和线性部分最小二乘（PLS）回归相结合的建立软测量模型的方法，并将它用于催化重整稳定油组分的估计中。仿真结果表明扰动分类法和PLS回归相结合建立的软测量模型简单、实用。     

Development of a Multi-Criteria Decision-Making Approach for Evaluating the Comprehensive Application of Herbaceous Peony at Low Latitudes

The growing region of herbaceous peony (Paeonia lactiflora) has been severely constrained due to the intensification of global warming and extreme weather events, especially at low latitudes. Assessing and selecting stress-tolerant and high-quality peony germplasm is essential for maintaining the normal growth and application of peonies under adverse conditions. This study proposed a modified multi-criteria decision-making (MCDM) model for assessing peonies adapted to low-latitude climates based on our previous study. This model is low-cost, timesaving and suitable for screening the adapted peony germplasm under hot and humid climates. The evaluation was conducted through the analytic hierarchy process (AHP), three major criteria, including adaptability-related, ornamental feature-related and growth habits-related criteria, and eighteen sub-criteria were proposed and constructed in this study. The model was validated on fifteen herbaceous peonies cultivars from different latitudes. The results showed that ‘Meiju’, ‘Hang Baishao’, ‘Hongpan Tuojin’ and ‘Bo Baishao’ were assessed as Level I, which have strong growth adaptability and high ornamental values, and were recommended for promotion and application at low latitudes. The reliability and stability of the MCDM model were further confirmed by measuring the chlorophyll fluorescence of the selected adaptive cultivars ‘Meiju’ and ‘Hang Baishao’ and one maladaptive cultivar ‘Zhuguang’. This study could provide a reference for the introduction, breeding and application of perennials under everchanging unfavorable climatic conditions.     

能力为本理念下三段教学法在无机及分析化学实验教学中的应用

文章提出了实验教学以能力为指向的教学目标思想。基于这个思想,对无机及分析化学课程实验教学的改革,提出了以能力为本理念下的三段式教学法,按能力要求由低到高依次为:基本实验操作阶段;综合实验阶段;自主设计实验阶段。     

Characterization of the Active Sites on Pt-Loaded ZSM-5 (Pt/ZSM-5) Prepared by an Ion-Exchange Method for the Oxidation of CO at Low Temperatures

Highly dispersed Pt-loaded ZSM-5 (Pt/ZSM-5) catalysts were prepared by a combination of ion-exchange and thermal pretreatment in different temperatures under vacuum. Highly dispersed ion-exchanged Pt²⁺ ions were reduced into Pt⁺ and then Pt⁰, sustaining their high dispersion state with an increase in the thermal pretreatment temperatures up to 773 K. Thus, prepared Pt⁰ highly dispersed in the cavities of ZSM-5 exhibited high catalytic activity for the oxidation of CO with N₂O at 273?K. However, pretreatment at temperatures higher than 973 K led to the aggregation of highly dispersed Pt⁰ clusters, resulting in a decrease in the catalytic activity for low-temperature oxidation.