The impact of air contaminants on PEMFC performance and durability

The impact of air contaminants such as sulfur compounds (SO₂, H₂S) and nitrogen compounds (NO_x and NH₃) was investigated using subscale fuel cells. The severity of the effect of these impurities varies depending on the contaminants. Among air contaminants, sulfur compounds cause the most severe performance loss due to decrease of available Pt sites for oxygen reduction reaction (ORR). We found that sulfur compounds adsorbed on Pt surface tend to be oxidized to sulfate at 0.9 V and higher potentials. The cell performance can be recovered partially by excursions to high potentials due to increase of available Pt sites. Furthermore, flushing the cathode with high humidity gases results in almost complete recovery of the cell performance. We conclude that these recovery effects are due to oxidation/removal of the contaminants from the Pt surface.     

低频声波振动采油技术在低渗透油田适应性探讨

针对大庆长垣外围低渗透油田,采用低频声波振动采油技术,对近井地带存在污染井进行振动解堵。低频波作用于饱和的油气水层时,可以提高渗透率,促使液体加速流向声源,向井眼聚集,同时分解出的气泡脉动穿过岩石的空隙疏通孔道,可以达到降黏、脱蜡、防垢的效果。一定频率的振动波在不同地层渗透率条件下的处理效果是不同的。低频波(1～300Hz)不易衰减,传播距离远,较适合在低渗透油田应用。现场共试验应用20口井,措施初期有效15口,有效率75.0%。目前正常生产19口井,有效11口,已累计增油1494t。从效果分析看,在压裂有效期内的井均无效。该技术适用于因作业或洗井等原因造成油层污染、产量下降的井;投产以来产量递减异常井;压裂有效期短的井。今后应针对不同的油层及油井特性,将适当的方法组合起来,开发出更有效、更经济的声波采油技术。     

发动机润滑油的环境影响

从润滑油的基础油与添加剂的组成和内燃机工作过程中气体污染物与微粒的生成机理出发,分析了润滑油对内燃机气体污染物、微粒物和后处理装置的影响。对内燃机使用中和报废后的废弃润滑油对水系或土壤等的环境影响也进行了分析。结果表明,随着排放标准的不断加严,润滑油对内燃机污染物生成量及后处理系统性能的影响逐渐变大．控制发动机润滑油的环境危害变得更为紧迫。     

激光诱导击穿光谱技术在燃煤电厂及土壤污染物在线检测中的应用研究

介绍了自主研发的激光诱导击穿光强技术（LIBS）煤质在线检测设备,可完成自动取样并带有自清洁系统,能实时对电厂输煤管道中煤粉的C、Ca、Mg、Ti、Si、H、Al、Fe、S等元素进行自动定量分析并转化为工业分析（发热量和灰分）结果。提出了飞灰含碳量在线检测成套方案并研制了自动采样及LIBS检测装置,建立了去除C线中Fe线的数学方法,利用二阶多元非线性逆回归模型建立了定标方程来校正基底效应,获得了0.26%的C元素测量精度。开发了便携式LIBS设备用于土壤污染物的现场检测,可对土壤中的重金属污染物进行快速的定性分析。     

Occurrence of priority organic pollutants in the fertilizers, China

The use of large quantities of chemical fertilizers is usually associated with environmental problems. A lot of work has been done on the concentrations of heavy metals and radionuclides in chemical fertilizers, but little work has focused on the occurrence of semi-volatile organic compounds (SVOCs). In this study the occurrence of 43 SVOCs listed as priority pollutants in 22 widely used-fertilizers of China was determined by gas chromatography coupled with mass spectrometry. Twenty-six SVOCs were detected with different detection frequencies and concentrations. The most abundant compounds were phthalic acid esters (PAEs; ranging from 1.17 to 2795 microg kg(-1) dry weight, d.w.) and nitroaromatics (up to 9765 microg kg(-1) d.w.), followed by polycyclic aromatic hydrocarbons (PAHs; <140 microg kg(-1) d.w.) and halogenated hydrocarbons (<900 microg kg(-1) d.w.). Chlorobenzenes and haloethers occurred generally at low concentrations. There are large variations in concentrations of various compounds in different fertilizers, and the total concentrations of each class of contaminants varied widely, too. The highest levels of sum concentration for 16 PAHs, for 6 PAEs and for nitroaromatics were found in organic fertilizer containing pesticide and soil amendments. Concentrations of SVOCs in coated fertilizers (the controlled release fertilizer with coating) were considerably higher than those in the corresponding fertilizers without coating. The occurrence frequencies of SVOCs in the straight fertilizers (containing only one of the major plant nutrients) were lower than in the other fertilizers.     

城市污水冷热源污水污杂物分级浓度测试实验

对污杂物的性质、形状以及分级浓度进行了定义,并通过实验在典型时段对哈尔滨市两处具有代表性的污水干渠进行了现场测定.实验结果表明,污水中大尺寸污杂物浓度平均高达1.0kg/m3.实验数据将为理论研究和工程设计提供参考.     

Research on Hot-line Cleaning of Artificial Contaminanted Insulator Using High Pressure Hot Water Vapor

The hot-line cleaning of insulator contaminants has a great significance to prevent pollution flashover.The technique of hot-line cleaning insulator contaminants by water vapor is proposed in this paper.The flashover characteristics of insulator under the procedure of cleaning by hot-line water vapor are tested to investigate the security of cleaning system in the operation.Three kinds of insulator are chosed to carry on the experiment.The average flashover voltage,flashover voltage gradient and withstand voltage in35 kV insulators in hot-line cleaning are measured.The results show that the average flashover voltage and withstand voltage of insulators used for hot-line water vapor cleaning are both larger than the operation phase voltage in 35 kV system.The flashover voltage gradient is larger than usual pollution flashover voltage gradient.The system security can be ensured when there is no overvoltage in the system,which verifies that the insulators cleaning method presented in this paper is effective and reliable.     

应用铁谱技术对液压泵污染磨损的试验分析

本文介绍了应用铁谱技术对液压泵在外来粉尘污染情况下磨损失效的试验分析结果。     

多目标约束下给水管网水质传感器选址优化算法的研究

利用EPANET2模拟扩展周期非稳态水力水质条件下管网节点污染物浓度变化,根据各个节点被注入污染物后,在管网模拟结束时得到的选址目标值的大小来确定节点有可能作为污染物注入的节点,目标值越大,该节点被选择的可能性越大.另外,本文提出了基本粒子群算法与遗传算法交叉、变异算子相结合的整数编码的优化算法来求解水质传感器选址问题,并编制了相应的计算程序.文中结合算例,以经过归一化后的节点平均坐标作为衡量选址结果的指标,得到了不同污染物注入开始时刻、注入持续时问和质量注入速率条件下传感器选址节点平均坐标的累计分布函数图,为传感器的选址提供参考.     

STUDY OF TURBULENT FLOW STRUCTURE AND CONTAMINANT DISTRIBUTION IN A 45°－BEND BY 3－D 2－LAYER MODEL

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