原子荧光光谱法测定空气中硒化氢的不确定度评定

依据JJF1059.1-2012,确立测量结果和不确定度评价的数学模型,从采集气样体积和采气后滤膜消解液待测物浓度和定容体积三个部分,A类不确定度和B类不确定度二个方面评定测量过程的不确定度,量化各不确定度分量。本次测量相对合成标准不确定度为0.024,较大的不确定度是样品浓度测量过程中的A类不确定度,主要由标准曲线测量和样品测量随机偏差引入,分量值分别为0.013和0.011。本次测量结果为0.169±0.008mg/m3(包含区间在0.161～0.177mg/m3),k=2。即在包含概率约为95%的条件下,可以判定该工作场所空气中硒化氢的含量已经超过了PC-TWA标准限值。     

丁二烯球罐中聚合物形成的影响因素

根据丁二烯聚合物形成的机理,通过自行搭建的实验装置,研究并确定了丁二烯过氧化物生成的影响因素。通过研究确定了温度对丁二烯过氧化物生成的影响,确定了氧含量和铁锈对丁二烯过氧化物生成的影响。根据不同因素对丁二烯过氧化物的影响,确定了球罐内丁二烯储存的临界温度和储存时间。丁二烯聚合的特点表明球罐内丁二烯二聚体含量偏高时,球罐发生爆聚的风险增加。为确保丁二烯球罐安全,必须严格控制球罐内二聚体含量、温度、铁锈含量和氧含量,紧急情况下须采取有效措施抑制丁二烯聚合。     

过氧化氢-敏化剂强化污泥微波预处理溶胞效果的研究

提高污泥溶胞效率是强化污泥厌氧处理的关键.为加强污泥微波预处理溶胞效果,本研究分别考察了常压、半封闭条件下二氧化钛颗粒、碳质材料作为敏化剂与过氧化氢联合进行微波污泥预处理的效果.结果表明,碳质材料敏化剂对微波、过氧化氢-微波污泥预处理产生了负作用,降低了污泥的溶胞效果,而二氧化钛能有效增加污泥中营养物质的释放.当二氧化钛颗粒投加量为0.12 g·g~(-1)干污泥时,SCOD、PO_4~(3-)-P的浓度比单独微波处理分别增加了11.86%、61%;当二氧化钛颗粒投加量为0.24 g·g~(-1)干污泥时,NH_4~+-N释放比单独微波处理高出27.78%.微波辐射作用下投加二氧化钛颗粒产生了羟基自由基,强化了过氧化氢-微波对污泥细胞的氧化作用.     

复合释氧剂的制备及其对水体修复的作用

采用腐殖酸钠、过氧化钙和沸石为原材料,在一定条件下制备复合释氧剂用于黑臭水体的生态修复。研究结果表明,复合释氧剂最佳制备条件为m(CaO_2)∶m(沸石)为1∶1、Na-A质量分数为2%和固化温度为100℃,复合释氧剂可显著延长释氧周期,且释氧过程对水体pH和COD的影响极低;底泥修复实验结果显示,复合释氧剂投加量为560 g/m~2时,上覆水溶解氧和氧化还原电位在第30天时分别维持在1.32 mg/L及42 m V,水中TP和COD去除率可分别达到90.11%和63%,表明复合释氧剂可有效改善水质并抑制底泥磷释放,这对城镇黑臭水体的生态修复治理具有一定的实际意义。     

双氧水与硫酸铝联用改善污泥脱水性能的试验研究

基于化学溶胞和絮凝剂单独调理污泥,均能在一定程度上改善污泥脱水性能。通过联用双氧水和硫酸铝对污水厂剩余污泥进行调理,分析两者联用对污泥脱水性能的改善效果,探求最佳的试验条件。将污泥脱水滤液回用至原泥(含水率80%),探求滤液回用在两种药剂联用下对脱水性能的改善效果。试验结果表明:在双氧水和硫酸铝联合调理下,污泥的脱水性能有明显改善;两者联用的最佳条件如下:初始污泥pH=3,投加2 mL/L(AR H_2O_2体积/湿污泥体积)的双氧水,调理60 min,再投加0.2 g/g的硫酸铝。     

Calorimetric studies on the thermal stability of methyl ethyl ketone peroxide (MEKP) formulations

The energetic decomposition of methyl ethyl ketone peroxide (MEKP) and its formulations have long been known to present a significant risk. Indeed, MEKP has the highest number of reported decomposition incidents of all organic peroxides, many of which have led to significant numbers of fatalities, injuries and damage. It is noteworthy that incidents have been reported at all stages of the product lifecycle.This paper is derived from incident-investigation work and provides a summary of serious incidents involving MEKP, followed by details of calorimetric experiments performed to investigate thermal stability of representative MEKP formulations containing varying amounts of MEKP monomer. In particular we report the wide degree of variation that exists between commercial MEKP formulations, even between materials that are of the same nominal formulation. Such variations are detectable using differential scanning calorimetry (DSC).Follow-up studies performed on a representative MEKP formulation containing MEKP monomer indicate that a risk of decomposition exists at temperatures well below the reported self-accelerating decomposition temperature (SADT) of the products. As such, the experimental results reported here suggest that lower storage temperatures (commonly recommended by manufacturers to maximise shelf life) should be considered as being essential throughout the product lifecycle to reduce the risk of accidents in storage and transportation.     

Advanced oxidation of bromide-containing drinking water：A balance between bromate and trihalomethane formation control

Addition of H2O2 has been employed to repress bromate formation during ozonation of bromide-containing source water. However, the addition of H2O2 will change the oxidation pathways of organic compounds due to the generation of abundant hydroxyl radicals, which could affect the removal efficacy of trihalomethane precursors via the combination of ozone and biological activated carbon （O3-BAC）. In this study, we evaluated the effects of H2O2 addition on bromate formation and trihalomethane formation potential （THMFP） reduction during treatment of bromide-containing （97.6-129.1 μg/L） source water by the O3-BAC process. At an ozone dose of 4.2 mg/L, an H2O2/O3 （g/g） ratio of over 1.0 was required to maintain the bromate concentration below 10.0 μg/L, while a much lower H2O2/O3 ratio was sufficient for a lower ozone dose. An H2O2/O3 （g/g） ratio below 0.3 should be avoided since the bromate concentration will increase with increasing H2O2 dose below this ratio. However, the addition of H2O2 at an ozone dose of 3.2 mg/L and an H2O2/O3 ratio of 1.0 resulted in a 43% decrease in THMFP removal when compared with the O3-BAC process. The optimum H2O2/O3 （g/g） ratio for balancing bromate and trihalomethane control was about 0.7-1.0. Fractionation of organic materials showed that the addition of H2O2 decreased the removal efficacy of the hydrophilic matter fraction of DOC by ozonation and increased the reactivity of the hydrophobic fractions during formation of trihalomethane, which may be the two main reasons responsible for the decrease in THMFP reduction efficacy. Overall, this study clearly demonstrated that it is necessary to balance bromate reduction and THMFP control when adopting an H2O2 addition strategy.     

Hydrogen island: the story and motivations behind the Icelandic hydrogen society experiment

The paper describes the background, motivations and action plan for an extensive experiment with hydrogen (H) as an energy carrier in Iceland. The energy consumption of Iceland is described as well as the role of fossil fuel imports in the otherwise renewable energy scenario. The paper goes on describing the academic/political reasons for the drive towards the H economy experiment and the international consortium created to herald the work. Finally the paper describes the ongoing projects in Iceland and the anticipated development of H research and development in the country.     

有障碍物半开口管道内氢气燃烧数值模拟研究

基于有障碍物氢气燃烧实验装置进行数值模拟研究,采用Fluent软件分析了半开口管道内障碍物对氢气/空气燃烧特性的影响。结果表明:障碍物会促进实验管段内氢气火焰加速,随着障碍物阻塞率和数量的增加,火焰加速更快且燃烧压力峰值更大;在相同阻塞率下,障碍物形状对氢气火焰速度和燃烧压力峰值的影响很小;燃烧压力随障碍物间距的增大先增大后减小,障碍物间距为3倍管道内径时产生的燃烧压力峰值最大。     

氢气爆燃作用下核电站安全壳力学响应数值模拟分析

在核电站严重事故中,由氢气爆燃产生的压力载荷会危及安全壳完整性致其失效,进而造成放射性物质泄漏的严重危害。通过ANSYS/Fluent有限元数值模拟软件,建立了安全壳有限元模型,并对安全壳内氢气爆燃过程以及其力学特性进行了数值模拟研究,获得了氢气爆炸过程中的超压值、升压速率、安全壳变形以及压应力分布。结果表明:爆燃波传递引起压强升高,火焰阵面处压强最高,爆燃波所经区域超压疾速上升随后快速下降;爆燃作用下,顶部壳体和下部筒体连接区域混凝土位移最大,最大压应力也集中分布在该区域,最易受到破坏。获得的结论可为安全壳结构抗爆设计和安全性研究提供理论参考。