Deposition and Resuspension of Selected Aerosols Particles on Electrically Charged Filter Materials for Respiratory Protective Devices

The primary aim of the study was to analyse the non-steady state of filtration for selected electrostatic filter materials designed for use in respiratory protective devices. The obtained results showed that the filtration process in electrostatic filters was dependent in the main on the following factors: type of the filter material, electrostatic field strength of the material, and the charge of the aerosol.

To a lesser degree the filtration process depended on the sign of the charge and the relative humidity of the air. A significant correlation was found between the increase in the penetration and the decrease in breathing resistance while the filter was being loaded.

The effect of resuspension (tearing off and re-deposition of dust agglomerates inside the filter) on the filtration process very significant. It was also observed that under certain conditions electrostatic filter materials lost their protection properties.     

Deposition and resuspension of selected aerosols particles on electrically charged filter materials for respiratory protective devices.

The primary aim of the study was to analyse the non-steady state of filtration for selected electrostatic filter materials designed for use in respiratory protective devices. The obtained results showed that the filtration process in electrostatic filters was dependent in the main on the following factors: type of the filter material, electrostatic field strength of the material, and the charge of the aerosol. To a lesser degree the filtration process depended on the sign of the charge and the relative humidity of the air. A significant correlation was found between the increase in the penetration and the decrease in breathing resistance while the filter was being loaded. The effect of resuspension (tearing off and re-deposition of dust agglomerates inside the filter) on the filtration process very significant. It was also observed that under certain conditions electrostatic filter materials lost their protection properties.     

水膜预湿行为对典型保温材料燃烧抑制实验研究

为探索喷淋形成水膜的预湿行为对外立面典型保温材料燃烧抑制机理,采用自建水膜预湿抑制保温材料燃烧实验装置,研究外加辐射作用下,水膜流率对聚苯乙烯(PS)保温材料表面出现干斑、变形和熔融的影响规律.结果表明:实验结束时PS材料表面水膜出现干斑、材料发生变形和熔融面积占比均与无量纲辐射强度呈正相关;PS材料表面水膜出现干斑、...     

外置植物碳源型人工湿地系统反硝化脱氮效果及N2O释放

人工湿地系统在处理低碳氮比污水时,通过外加碳源来提高系统的脱氮效率。碳源是反硝化过程中重要的影响因素,对N_2O释放必然也产生影响。采用芦苇(Phragmites australis)和二球悬铃木(Platanus acerifolia)树叶为碳源的外置碳源型的人工湿地系统,以葡萄糖作为对比碳源,研究有机碳源对脱氮效果及N_2O释放量的影响。结果表明,芦苇和悬铃木树叶作为碳源,在植物分解稳定后,脱氮效果稳定,TN平均去除率分别为90.3%和92.5%,比空白组高出15%左右;单批次试验中,芦苇组和树叶组N_2O平均释放量分别为40.91μg/(m~2·h)和34.16μg/(m~2·h),略高于葡萄糖组的6.20μg/(m~2·h),但显著小于空白组的127.45μg/(m~2·h),累积释放量与TN去除量的比值小于0.1%且显著小于空白组;芦苇和树叶组基质微生物的反硝化作用强度及PLFAs总量均显著高于空白组,细菌PLFAs占PLFAs总量的比例均接近50%,而真菌PLFAs仅大于7%,细菌为优势种群。因此,向处理低C/N污水的人工湿地系统补充适宜的植物碳源材料,可以有效提高脱氮效率并降低N_2O释放。     

Numerical simulation and experimental study on metallographic structure characteristics of melting trace caused by overcurrent fault of copper wire

The microscopic characteristics of melting trace caused by copper wire fault are an important basis for the physical evidence identification of electrical fires. Metallography is an important method in electrical fire research, and computer-aided quantitative analysis on metallographic structure is common in materials aspect. In this study, the metallographic structure and phase composition characteristics of melting trace caused by overcurrent fault were explored with the aid of a metallographic microscope and an X-ray diffractometer (XRD). The results show that the grains are mainly slender dendritic and columnar crystals when the current is 128 A, while they are coarse dendritic and cellular crystals when the current is greater than 192 A; the average grain diameter of melting trace of copper wire grows with the increase in current. The main phases of melting trace caused by overcurrent fault of copper wire are α-Cu base and Cu₂O, and the new phases Cu₄Si and Cu₂Mg are formed when the current is higher than 160 A. In addition, the solidification process of metallographic structure of copper wire under different currents was simulated by the Procast software. It is found that the simulation results are basically in agreement with the experimental data, which suggests that this model can effectively predict the microstructure characteristics of melting trace of copper wire under different currents. The research results can provide a sound basis for the physical evidence identification of electrical fire and improve the accuracy and scientificity of electrical fire investigation.     

改性钢渣除磷试验研究

研究了改性钢渣的吸附除磷效果。试验结果表明，钢渣对废水中的磷的去除率较高，当废水中磷质量浓度为10mg／L，pH值为弱酸或弱碱性条件下，钢渣的用量1g/100mL时，在15min内就可使残留液质量浓度降低到0．1mg／L，远远低于国家排放标准，去除率达到99％以上，对水体富营养化处理具有很重要的意义。     

浅谈压力容器制造过程中的材料监检

加强制造过程中对材料的质量控制与监督检验,确保材料选用得当、材料质量过关,是保证压力容器产品质量的前提条件。本文以钢制压力容器为例,结合相关规范、标准,从材料质量证明书、材料标准、熔炼方法、化学分析、材料复验、材料代用等角度阐述了压力容器制造监检过程中的些许案例与经验。     

Strain hardening effect of CF8M stainless steel in the environment fatigue test under pressurized water reactor condition

To develop a fatigue design curve of cast stainless steel CF8M that has been used in piping material of nuclear power plants, a low cycle fatigue tests were conducted in the environment of a pressurized water reactor at 15 MPa and 315 °C. Cylindrical solid fatigue specimens were used for the strain-controlled environmental fatigue tests. Fatigue life was measured in terms of the number of cycles with the variation of strain amplitudes at 0.04%/s strain rate. This paper focuses on the characteristics of the cyclic strain hardening effect caused during environment fatigue tests of the CF8M cast stainless steel. The process and method of correcting fatigue test data in this paper would be so useful to produce reliable data of environmental fatigue curves for the material in operating condition of high pressure and high temperature water environments.     

Efficiency of Filtering Materials Used in Respiratory Protective Devices Against Nanoparticles

The basic aim of this research was to establish the efficiency of filtering materials widely used in respiratory protection devices with particular interest in their porosity, degree of electric and changeable process parameters, such as the flow rate of the test nanoaerosol and the size range of nanoparticles. Tests were carried out with an NaCl solid aerosol of 3.2 × 10⁵ particles/cm³ for the range of particle size of 7–270 nm, at aerosol flow rate of 1800, 2700, 3600, 4500 and 5400 L/h. The tests showed that electrospun nonwovens were the most effective filtering materials for nanoparticles over 20 nm. Melt-blown electret nonwovens with lower porosity than electrospun nonwovens had higher values of penetration of 1%–4%. Those materials provided very efficient protection against nanoparticles of certain sizes only.     

磨料水射流除鳞技术在钢厂的应用

为了暴露各种钢材在热轧过程中产生的表面缺陷，需清除附于其上的氧化铁皮，称之为“除鳞”。传统的除鳞方法有酸洗、表面剥皮、喷丸处理等，这些方法存在很多缺点。本文介绍已在湖南涟钢用于生产的磨料水射流除鳞生产线，用磨料水射流除鳞具有速度快、质量高、成本低、操作简便等独特的优点。     

氯乙烯储罐注水堵漏腐蚀风险的预测方法研究*

为更好地解决氯乙烯储罐注水堵漏可能导致储罐发生腐蚀泄漏的实际问题,提出1种基于ASPEN和神经网络的氯乙烯储罐注水堵漏腐蚀风险的预测方法。运用ASPEN流程模拟软件,对氯乙烯储罐注水堵漏工艺进行模拟,得到不同泄漏孔径下注水速率和HCl浓度的关系;以HCl浓度作为导致腐蚀的主要影响因素,对不同种钢材进行挂片腐蚀实验;结合神经网络分析,得出HCl浓度与腐蚀速率之间的拟合式,预测储罐腐蚀情况。结果表明:神经网络预测结果平均相对误差7.63%,随注水速率的提高,HCl浓度变化呈下降趋势,腐蚀速率变化呈下降趋势;在等效泄漏孔径24 mm、注水速率0.87 m/s时,Q345R腐蚀速率13.93 mm/a,20#腐蚀速率10.48 mm/a,201不锈钢腐蚀速率7.09 mm/a为3者中最低,但此工况下,201不锈钢有点蚀倾向,储罐易发生穿孔,故201不锈钢不宜用作氯乙烯储罐母材,并提出对《石油化工企业设计防火标准(2018年版)》的修订建议。     

翻车机室除尘密闭罩设计

针对钢铁厂物料矿石转运过程中,翻车机卸料时,物料落差大、产生的扬尘大且弥漫范围广、翻车机工艺设备复杂等特点,介绍了翻车机工艺系统的特点及密闭罩的设计。实践证明,该密闭罩的设置实用可行,可推广于同类翻车机室的除尘。     

3级生铁过滤-厌氧-生物接触氧化法处理糠醛废水研究

糠醛是重要的有机化工溶剂和生产原料.目前糠醛生产企业的环保治理还没有跟上生产的发展,三废污染相当严重,废水的COD高,酸性强,直接排放对当地的地下水造成严重污染.糠醛行业的污染问题已经成为制约糠醛生产的瓶颈因素和亟待解决的重大课题.就糠醛生产工艺与生产废水水质特点,采用3级生铁过滤-厌氧-生物接触氧化法治理糠醛废水.运行结果表明,糠醛废水经处理后,COD的总去除率达到98%以上,出水pH6-9,符合国家《污水综合排放标准》(8979-1996)中2级排放标准的要求.     

螺纹自动退刀安全防撞装置

高速车削螺纹退刀时，若退刀不及时，极易发生事故。设计了一种装置——螺纹自动退刀安全防撞装置，从而解决了高速车削螺纹退刀困难等一系列问题。     

Prediction of minimum ignition energy of aerosols using flame kernel modeling combined with flame front propagation theory

Flammable aerosols have created many fire and explosion hazards in the process industry, but the flammability of aerosols has not been fully understood. The minimum ignition energy has been widely used as an indicator for flammability of combustible mixtures, but the amount of experimental data on the minimum ignition energy of aerosols is very limited. In this work, the minimum ignition energy of tetralin aerosols is predicted using an integrated model. The model applies the flame front propagation theory in aerosol systems to the growth of the flame kernel, which was created during the spark discharge in the ignition process. The aerosol minimum ignition energy was defined as the minimum level of energy in the initial flame kernel to maintain the kernel temperature above the minimum ignition temperature of 1073 K specific for tetralin aerosols during the kernel growth. The minimum ignition energy obtained in the model is influenced by the fuel-air equivalence ratio and the size of the aerosol droplets. For tetralin aerosols of 40 μm diameter, E_min decreases significantly from 0.32 mJ to 4.3 × 10 e⁻³ mJ when the equivalence ratio rises from 0.57 to 1.0. For tetralin aerosols of 0.57 equivalence ratio, E_min increases from as 0.09 mJ to 0.32 mJ when the droplet diameter rises from 10 μm to 60 μm. The trends are in agreement with previous experimental observations. The method used in current work has the potential to prediction of the minimum ignition energy of aerosol.     

某处理厂CASS池改造工艺选择及运行效果

随着污水处理厂排到受纳水体标准的不断提高及区域污染物排放限值的要求,已建的污水处理厂需要提标改造提高排放标准。本文所提工程对现有的CASS池进行改造,通过投加悬浮填料形成CASS+MBBR工艺,其中TN污染物的去除率可提高到8%~15%间,其它污染物也能达到预期的设计标准。     

TSLCDM长袋低压脉冲布袋除尘器及其应用

为了使电炉烟气治理过程中污染源的排放达到国家排放标准,提出一种TSLCDM长袋低压脉冲除尘器(简称TSLCDM除尘器)。通过对该除尘器结构、除尘原理以及不同工况下除尘效率和过滤阻力的分析,得到该除尘器的除尘效率>99.9%,压力损失<1200 Pa,最终排出的烟气含尘质量浓度约5.54 mg/m3,满足了国家的超低排放要求,以泉州某公司电炉项目除尘系统为研究对象,证明了该新型脉冲布袋除尘器在电炉烟气治理除尘系统的应用效果,具有很好的经济和环境效益。     

新型电极体系电解处理高浓度酸性TNT废水的研究

通过大量试验研究了电解处理TNT废水的条件,尤其是筛选、制备了多种电极材料,在三维电极体系,低电流、短时间条件下电解处理TNT的去除率达到95%以上,pH值提高至6以上,大大节省了能源,为火炸药工业酸性TNT废水的处理提供了一种新型有效的处理方法.用本方法对实际工业"黄水"进行电解处理,获得了较为满意的效果.     

农村变电站生活污水处理现状与探讨

我国大部分变电站位于农村地区,因无接入城市污水管网条件,农村变电站生活污水需就地处理后达标排放。变电站生活污水存在水量少、时变化系数大等特点,现有处理工艺不能正常运行或无法达标排放。本文借鉴农村生活污水处理技术,提出了生物组合法处理对策,可为变电站生活污水处理提供参考。     

钢渣堆场扬尘定量计算与控制措施分析

通过对天津钢铁集团有限公司钢渣加工处理过程及钢渣堆场进行现状监测及建模分析,得出不同条 件下钢渣加工及堆存的实际扬尘量,并提出切实有效的环境管理控制措施,为冶金企业在走可持续发展道路过程中降低污染排放、规避环境风险提供了理论依据和技术支撑.