轻质油品铁路装车系统的改造

针对近年来企业轻质油品铁路装车系统改造过程中需要注意的几个问题进行了危害性分析,并提出了整改方案：栈台改造时要确保罐车与栈台边缘的距离满足安全间距;确保鹤管和罐车的准确对位;装车流速的控制即要考虑铁路部门不超过3h的要求,也要满足安全流速的要求;装车泵宜选用变频技术;不同油品的鹤管必须分开设置;装车前罐车内的残油和鹤管管线中的残油应进行回收处理;密封盖的选型应考虑密封面的形式和装车过程中车辆的下沉等因素;油气回收设施与栈台的距离不应超过800mm,油气回收主管线的直径可根据实际装车泵最大流量进行核算。     

Hg Vapor Emission from Broken Compact Fluorescent Lamps (CFLs) in an Acrylic Chamber

The United States Environmental Protection Agency/Environmental Response Team (US EPA/ERT), in collaboration with St. John's College, Dr. B. R. Ambedkar University, Agra, India, is conducting a study to determine Hg vapor emission rates resulting from broken compact fluorescent lamps (CFLs) in a residential setting. The overall objectives of the study are to determine Hg vapor emission data and provide homeowners with cleanup procedures and disposal options for broken CFLs. Most of the currently available CFLs in the US market are manufactured in China for US companies. Several different types of CFLs were purchased from local stores and their Hg content was determined. Based on previous studies, such as the 2011 study by Singhvi and colleagues, five popular spiral CFLs were selected for emission studies in an acrylic chamber. This study found that Hg vapor emissions from CFLs may be significantly greater than those from beads of liquid Hg with weights comparable to the Hg content of the CFLs. The average 24-hour Hg loss into the atmosphere from CFLs broken on a plastic surface ranged from 0.6% to 22% of the bulb content, while that for CFLs broken on carpet ranged from 2.6% to 28%. Projections for a 12 foot × 9.33 foot × 8 foot (25.4 m³) room based on the chamber measurements in this study indicate that CFL breakage in some household settings may produce 24-hour Hg concentrations above the 2000 Agency for Toxic Substances and Disease Registry (ATSDR) minimum risk level (MRL) of 0.2 μg/m³, for typical air exchange rates. This study also indicates that Hg emission may not be proportional to exposed surface area based on experiments using liquid Hg with different surface areas.     

加油站油气扩散与回收效果的数值分析

加油站排放出的油气是有毒有害的气体。目前控制油品蒸发损耗的有效方法是采用油气回收系统。基于湍流模式理论,采用FLUENT软件,模拟加油站在使用油气回收系统前后空气中油气浓度分布情况及风对油气扩散的影响,得到油气浓度等值面图、直线及点上浓度变化曲线图。模拟结果表明,实施油气回收,其大气净化率可高达95％以上,因此明显减小加油站火灾隐患及环境污染,并可减少经济损失及节约加油站占地面积。另外,风对油气扩散稀释有明显的影响,如距排放口下风侧5 m处,相对于风速１ m/s,风速为5、8 m/s时的大气净化率分别为54％、71％。虽然无法降低油气排放总量,但是随着风速的增加大气净化率随之变大,可以减少油气浓度值过高造成的危害。     

有障碍物开敞空间可燃气云爆炸超压场的数值模拟

利用计算流体动力学软件AutoReaGas定量研究障碍物、障碍物阻塞比对开敞空间可燃气云爆炸超压场的影响以及爆燃超压随测点距离变化的分布规律。研究结果表明:当有障碍物存在时,爆炸峰值超压会显著增加,且峰值超压随着障碍物阻塞比的增加而增加。对于有障碍物条件下开敞空间的丙烷气云爆炸,无论是气云内部还是气云外部,随着距爆心距离的增加,峰值超压都有减小的趋势。     

Investigation of partitioning mechanism for volatile organic compounds in a multiphase system

Laboratory experiments were performed to investigate the partitioning behavior of a set of diverse volatile organic compounds (VOCs). After equilibration at a temperature of 25 °C, the VOC concentrations were measured by headspace method in combination with gas chromatography/mass spectrometry (GC/MS). The obtained data were used to determine the partition coefficients (K_P) of VOCs in a gas-liguid-solid system. The results have shown that the presence and nature of solid materials in the working solution control the air-water partitioning of dissolved VOCs. The air/solution partitioning of BTEX and C₉-C₁₀ aldehydes was most affected in the presence of diesel soot. K_P values decreased by a factor ranging from 1.5 for toluene to 3.0 for ethylbenzene. The addition of mineral dust in the working solution exhibited greater influence on the partitioning of short aldehydes. K_P values decreased by a factor of 1.8. The experimental partition coefficients were used to develop a predictive model for partitioning of BTEX and n-aldehydes between air, water and solid phases.     

低渗透岩石结构体风化初期的水气分子扩散

低渗透岩石具有孔隙狭窄、连通性差、流动阻力大等特点,这致使地下水渗流速度极低。本文以二长岩及玄武岩结构体的核心及紧靠核心的外环区域为对象对低渗透岩石结构体的初期风化机理进行研究。二长岩及玄武岩核心区的渗透率分别为0.0047×10-3μm2和0.0081×10-3μm2,孔隙度分别为1.58%和0.24%。对两种岩石的核心及外环进行化学全分析表明两个区域的主要元素含量无明显变化,外环烧失量有所增加,Fe2+与Fe3+变化敏感。薄片鉴定发现二长岩核心及外环的斜长石及钾长石均发生了强烈风化,外环中的辉石变为绿泥石。玄武岩的核心区矿物基本无变化,外环的长石及辉石发生了皂石化,部分基质绿泥石化。微观结构上,两种岩石核心区均致密坚硬,外环不同程度地出现了长石及辉石的晶内溶孔。风化初期,水以气态形式扩散进入低渗透岩石内部。水气的扩散方式为介于菲克型扩散与Knudsen扩散之间的过渡型扩散。计算得二长岩和玄武岩中的水气扩散系数分别为48.09×10-8m2/s和3.74×10-8m2/s。