焊接车间烟尘治理系统探讨

众多中小加工企业生产车间在焊接作业过程中会产生大量焊接烟尘等有毒物质,对焊接工人的身体健康造成严重危害,由此产生的电焊工尘肺职业病呈多发趋势,同时焊接烟尘还会影响厂区周边的大气环境。根据整个焊接车间中焊接设备加工情况及通风状况的分析及现场实际应用,研究设计出适合该场合的烟尘治理系统。     

石家庄道路灰尘中全氟/多氟化合物及其新型替代品的污染特征及健康风险评估

为探究石家庄市道路灰尘中全氟/多氟化合物(PFASs)的污染特征,利用高效液相色谱-串联质谱法(HPLC-MS/MS)分析主干和次干道路灰尘样品(部分采集于污水处理厂和消防站附近)中包括两类新型替代品在内的22种PFASs.结果表明,PFASs在石家庄道路灰尘中普遍存在,特别是新型替代品——六氟环氧丙烷二聚酸(HFPO-DA)的检出属国内首次.∑PFASs含量范围为2.62～137.65 ng·g^-1,全氟辛酸(PFOA)为主要组分,其次为全氟丁酸(PFBA)、 HFPO-DA和全氟辛基磺酸(PFOS).空间分布上,西北方向PFASs含量水平最高,东南方向最低.污水处理厂和消防站附近道路灰尘中PFASs组成存在明显不同,特别是新型替代品的检出类型.健康风险评估结果显示,道路灰尘摄入对于人体暴露PFASs和其新型替代品的风险相对较低.经口、呼吸道和皮肤接触3种途径中,经口摄入是目标化合物进入人体的主要途径.在同一暴露途径下,儿童的暴露量高于成人.     

Optimization via response surface methodology of the synthesis of a dust suppressant and its performance characterization for use in open cut coal mines

To relieve dust pollution in open cut coal mines and reduce the hazards of coal dust pollution to the environment and workers we optimized the synthesis of a dust suppressant by graft copolymerization of environmentally friendly soy protein isolate with methyl methacrylate. This dust suppressant could effectively control dust pollution in open cut coal mines. The optimized conditions for graft copolymerization in this case were determined by a response surface experiment designed with Design-Expert 10 software. Characterization by scanning electron microscopy showed a significant morphology change of the dust suppressant and the generation of a rigid and dense layer on its surface after interacting with coal dust. The layer exhibited good bonding and dust suppression performance. The analysis with Fourier-transform infrared spectroscopy revealed the appearance of new absorption peaks near 1300, 1072, and 1631 cm⁻¹, demonstrating effective graft copolymerization. The proposed dust suppressant exhibited excellent wind erosion resistance, with a resistance that exceeded 90% at a wind speed of 6.5 m/sec. The successful graft copolymerization and effective bonding and curing of the dust suppressant on coal dust were experimentally verified. This is of great significance to the control of coal dust pollution.     

适应低排放的电除尘技术探讨

针对高标准的排放要求以及将进一步提高的排放标准,对电除尘器是否能满足目前的排放标准和低排放要求进行了研究。通过对国内110个机组配套电除尘器实际应用情况调查和国外燃煤机组电除尘器应用分析,客观地评价了电除尘器对国内煤种的适应性,指出移动电极式电除尘器、双极异距电流体微粒聚合器、烟气调质、湿式电除尘器、低低温电除尘器等新技术的发展和综合应用是满足30mg/m3低排放标要求的最佳选择。     

Analysis of herbicide residues by gas chromatography

The extraction and clean‐up, and gas Chromatographic conditions for the detection and determination of herbicides, their metabolites and related compounds are reviewed. The literature material is examined critically in the text and presented in tabular form for quick reference. The section dealing with extraction/clean‐up techniques is sub‐divided with respect to water, soil, plant material, animal, fish and micro‐organisms. Under eight herbicide group headings the important gas Chromatographic parameters such as stationary phase, support phase, column temperature and mode of detection are tabulated. Also tabulated are the application of various detectors to herbicide analyses and limits of detection where information was available. Most commonly used liquid and support phases are listed and their frequency of use given. Different aspects of derivative formation used for the positive identification and quantitation of herbicides are discussed with emphasis on esterification, alkylation and silylation. Other important conversion techniques are outlined, particularly those associated with enhancement of sensitivity e.g. bromination, iodination, dinitrophenylation etc. Efforts that have been made towards general and automated analytical methods are discussed.     

Observations of microscopic characteristics of post-explosion coal dust samples

To reveal the microscopic characteristics of the post-explosion coal dust samples, coal dust explosion tests were performed in a 20 L spherical vessel. The explosion characteristic parameters, such as the maximum pressure (P_max), the maximum rate of pressure rise ((dP/dt)_max), ignition time (t) and the deflagration index (K_St) were recorded. Meanwhile, the post-explosion dust samples were collected and analyzed. The research efforts include particle size distribution analysis, SEM analysis and FTIR analysis of dust samples before and after the explosion. The particle size range of post-explosion dust samples became wider according to the mass percent analysis. The microscopic appearance of samples in same particle size range showed some similarity. The porous structure of dust samples was observed by improving the SEM magnification. The chemical structure of dust samples before and after explosion was analyzed by FTIR.     

福州市区街道灰尘中多环芳烃的质量分数及其来源

采用超高效液相色谱系统(UPLC)荧光检测器法,测定了福州市区14条主要街道灰尘样品中属美国环境保护署(US EPA)优控的15种多环芳烃(PAHs)的质量分数,对其毒性进行了评估,并通过聚类分析、因子分析/多元线性回归等方法,分析了灰尘中PAHs的来源. 结果表明:福州市区的w(PAHs)为1 029.5～5 182.0 μg/kg,平均值为2 884.7 μg/kg,在国内外城市中处于中等含量水平. 14个街道灰尘样品中有5个样品的w(PAHs)超过毒性效应区间低值(ERL),具有潜在的生态风险. 聚类分析发现,4号,5号,7号和12号采样点分别具有高比例的w(菲),w(苯并［b］荧蒽),w(荧蒽)和w(萘)的特殊来源.对样品中PAHs的来源解析显示,燃烧源占78%,石油泄漏源占22%.      

天津钢管100t电炉除尘工程

天津钢管100t电炉除尘项目为适应电炉的操作及提高烟气捕集率,减少除尘系统烟气量,采用第四孔捕集一次烟气,电炉跨屋顶罩捕集二次烟气的组合方式,间接水冷,间接风冷,混风降温的干法除尘,效果显著。针对此工程,分析除尘系统在设计、施工、运行中需要注意的关键技术,并对除尘工艺的发展作了前瞻性的探讨。     

北京市地面街尘与径流中重金属的污染特征（Characteristics of Heavy Metals in Street Dusts and Urban Runoff in Beijing）

街尘作为城市各种污染物的载体和地表径流污染物的主要来源对水环境的影响日益受到关注.论文分析了北京市城区街尘与地表径流中重金属浓度和颗粒的粒径分布.结果表明:不同城市土地利用类型对街尘和径流中的重金属含量、颗粒粒径分布具有重要影响.在商业区、主要道路、住宅区、城中村4种土地利用类型中,街尘重金属浓度和地面单位面积重金属质量均以主要道路最高;径流重金属浓度由高到低顺序依次为:主要道路>城中村>居民区;主要道路和商业区街尘颗粒中细粒径占的比例较高,在全部土地利用类型的径流水样中颗粒物粒径分布差别不大;随着街尘中颗粒物粒径的减小,重金属浓度增加;街尘中小于149μm的颗粒物质量百分比和重金属浓度均较高,且在径流中这个粒径段的颗粒物含量也高,体积比达80%以上.建议在今后的城市街尘面源污染控制中应特别关注土地利用类型和街尘粒径的影响.     

贵阳市城市道路灰尘重金属铅污染及评价

对贵阳市城市道路灰尘重金属铅污染进行了研究。结果表明：2008年贵阳市各行政区道路灰尘中铅的含量按南明区、乌当区、白云区、花溪区、云岩区、小河区顺序分别为81.19～174.94mg/kg、54.33～177.62mg/kg、59.75～275.93mg/kg、59.45～143.41mg/kg、61.32～106.05mg/kg、57.84～115.53mg/kg,平均含量分别为110.94mg/kg、78.49mg/kg、105.35mg/kg、96.87mg/kg、81.51mg/kg、88.11mg/kg,分别为环境背景值的3.0倍、2.1倍、2.8倍、2.6倍、2.2倍、2.4倍;不同行政区铅含量存在较大差异,铅在空间分布上也存在较大差异,其中白云区差异最大,云岩区差异最小。地积累指数及铅污染指数评价表明：贵阳市城市道路灰尘中铅污染总体上处于轻度污染水平,但局部区域处于偏中度至中度污染水平。