煤矿瓦斯爆炸阻隔爆技术现状及展望

煤矿主要采用隔爆水棚或岩粉棚来抑制瓦斯爆炸火焰传播,但此类技术仅针对一次性瓦斯爆炸,而缺乏对多次及连续瓦斯爆炸的有效阻隔爆手段。仅注重对燃烧波的淬熄作用,对造成很大破坏的冲击波的衰减效果不足。多孔介质的淬熄火焰和衰减冲击波的效能已得到国内外专家的重视,实验研究了多层丝网和多孔材料如泡沫铝和泡沫陶瓷的阻隔爆效果。泡沫陶瓷作为一种多孔介质,具有开孔率大、耐高温、抗冲击力强的优点。理论分析和实验研究表明,由于壁面的多次撞击效应,多孔介质可以有效地销毁瓦斯燃烧化学反应产生的自由基数量,抑制化学反应的放热,使化学反应不能自持进行,进而淬熄燃烧火焰传播;可以大幅衰减瓦斯爆炸的冲击波强度,起到同时淬熄燃烧火焰和衰减冲击波的作用。多孔介质有望成为煤矿井下一种新型的瓦斯爆炸阻隔爆材料和方法。     

聚氨酯泡沫塑料中CFC-11总含量测定研究

提出一种全新的聚氨酯泡沫塑料中CFC-11总含量的测量方法.在密闭箱中将PUR硬泡破碎成粒径小于0.5 mm的细颗粒,使用GC/MS测量密闭箱中CFC-11浓度,得出破碎时释放出的CFC-11质量;将破碎的细颗粒用管式炉高温加热,使吸附于细颗粒中的CFC-11释放并用气样袋收集,使用GC/MS测量气样中CFC-11浓度,得出吸附于PUR硬泡固体中的CFC-11质量,最后将两者相加得出总含量.     

Italian WEEE management system and treatment of end-of-life cooling and freezing equipments for CFCs removal

This study presents and analyzes the data of the Italian system for take-back and recovery of waste electrical and electronic equipments (WEEEs) in the start-up period 2008–2010. The analysis was focused particularly on the data about the treatment of end-of-life cooling and freezing equipments. In fact, the wastes of cooling and freezing equipments have a high environmental impact. Indeed, in their compressor oil and insulation polyurethane (PU) foams chlorofluorocarbon (CFC) ozone-depleting gases are still present. In the period 2001–2004 Northern Italy resulted the main source in Europe of CFCs. The European Directive on WEEE management was enacted in 2002, but in Italy it was implemented by the legislative Decree in 2005 and it became operational in 2008. Actually, in 2008 the national WEEE Coordination Centre was founded in order to organize the WEEE pick-up process and to control collection, recovery and recycling targets. As a result, in 2010 the average WEEE collection per capita exceeded the threshold of more than 4 kg per inhabitant, as well as cooling and freezing appliances represented more than one fourth of the Italian WEEE collection stream. During the treatment of end-of-life cooling and freezing equipments, CFCs were recovered and disposed principally by burner methods. The analyses of defined specimens collected in the treatment facilities were standardized to reliably determine the amount of recovered CFCs. Samples of alkaline solid salt, alkaline saline solution, polyurethane matrix and compressor oil collected during the audit assessment procedure were analyzed and the results were discussed. In particular, the analysis of PU samples after the shredding and the warm pressing procedures measured a residual CFCs content around 500–1300 mg/kg of CFCs within the foam matrix.     

泡沫灭火剂环保性能评价及研究进展

泡沫灭火剂主要用于扑灭液体燃料火灾,是一类成分复杂的化学品。针对泡沫灭火剂的环境污染风险、国家标准《泡沫灭火剂》(GB 15308—2006)与《A类泡沫灭火剂》(GB 27897—2011)无环保性能指标等问题,介绍了各类泡沫灭火剂的环境污染风险,综述了国内外泡沫灭火剂环保性能评价方法的研究进展,对比了中国、美国、欧盟现行泡沫灭火剂标准中的环保性能评价指标与方法,指出:我国可采用生物毒性、BOD₅/TOC、总有机氟含量等作为泡沫灭火剂环保性能的评价指标。     

自养型生物过滤器硝化氧化一氧化氮

采用一种新的工程材料多孔碳作为填料,在3个φ50.8mm填充着不同孔径多孔碳和驯化培养好的自养型亚硝酸盐硝化菌的生物过滤器中,进行了净化气体中NO的探索性研究.实验采用亚硝酸盐为唯一氮源,在多孔碳的表面培养生物膜,采用超声波气溶胶发生器来维持过滤器内的湿度并保持多孔碳表面液膜的厚度较小.液相硝化试验用来比较3种不同孔径的多孔碳之间硝化性能的潜力和差异结果表明,在亚氮(NO₂^--N)进口负荷约200～800g/(L·min)的范围内.24孔/cm(Pores Per Centimeter,PPC)多孔碳过滤器的硝化速率最大,达到94%～98%;8PPC和18PPC多孔碳过滤器的硝化速率分别达到15%～21%和30%～40%.气相试验表明,在NO空床停留时间3.5min、进口浓度66.97～267.86mg/m³的范围内,24PPC多孔碳过滤器对NO的去除效率为41%～52%左右,表明了该自养硝化系统在NO废气治理中的应用潜力.     

常用聚氨酯硬泡外墙外保温系统的点燃特性研究

基于锥形量热仪实验,对常用的聚氨酯硬泡外墙外保温系统的点燃特性进行了实验研究。所研究的系统种类包括粘贴保温板薄抹灰外墙外保温系统,瓷砖饰面粘贴保温板外墙外保温系统,胶粉浆料复合保温板外墙外保温系统和保温装饰板外墙外保温系统。实验结果显示,聚氨酯硬泡保温板和聚氨酯硬泡外墙外保温系统都可由热厚型点燃描述。在防护层对点燃时间的抑制效果方面,胶粉聚苯颗粒复合保温板系统最好,瓷砖饰面系统稍差但明显好于5mm和3mm厚防护层的薄抹灰系统,铝板保温装饰板系统最差。     

泡沫铝填充结构救生舱多目标优化设计

为提高救生舱的安全性,设计了1种泡沫铝填充结构救生舱。利用Workbench对原型救生舱进行静力分析,以泡沫铝填充结构救生舱的内外板厚、泡沫铝厚、纵向和横向加强筋宽为设计变量,以原型救生舱的最大应力、最大位移以及模型质量为约束条件,以泡沫铝填充结构救生舱的静态最大应力、最大位移及质量为目标函数,分析各设计变量对目标函数的灵敏度并进行多目标优化设计;并利用数值仿真方法研究优化后的泡沫铝填充结构救生舱的抗爆炸冲击性能。结果表明:与传统救生舱相比,优化后的泡沫铝填充结构救生舱可以显著提高救生舱的静力及抗爆炸冲击能力,进而提高其安全性能。     

两相射流促进细水雾灭火技术发展

压缩气体射流与水射流混合后所产生的气-水两相射流,可获得连续、高速喷射的细水雾,水滴粒径小,穿入火焰的能力强,可沿水平方向射入火焰中,比喷淋方式水雾灭火可节省90%的用水量,缩短了灭火时间,发挥了细水雾的灭火优势,是细水雾灭火技术的最新发展。所制成的便携式、车载式、固定式的两相射流细水雾灭火装置,可扑灭多种类型的火灾,尤其适合用于扑灭有人存在的空间的火灾。以涡喷发动机为喷射动力的气-水两相射流喷射系统,制成了超大功率的喷射雾状水的消防装备,大幅度提高了控制油、气大火火势的能力和灭火效率。气-水两相射流还有稀释、吹散泄漏出的可燃性气体,防止其点燃的功能,适合于在天然气和有毒有害气体泄漏事故抢险救援中使用。将压缩气体和泡沫液按比例混和后喷射的压缩空气泡沫喷射系统,产生了喷射“干泡沫”的消防车,使灭火用水的利用率提高了8倍,被称为是世界最先进的泡沫灭火技术。气-水两相射流促进了灭火技术革命性的发展,新型的气-水两相射流消防装备不断涌现,展示出了广阔的应用前景。     

Reusable and disposable cups: An energy-based evaluation

A group of five different types of reusable and disposable hot drink cups have been analyzed in detail with respect to their overall energy costs during fabrication and use. Electricity generating methods and efficiencies have been found to be key factors in the primary energy consumption for the washing of reusable cups and a less important factor in cup fabrication. In Canada or the United States, over 500 or more use cycles, reusable cups are found to have about the same or slightly more energy consumption, use for use, as moulded polystyrene foam cups used once and then discarded. For the same area paper cups used once and discarded are found to consume less fossil fuel energy per use than any of the other cup types examined. Details of this analysis, which could facilitate the comparative assessment of other scenarios, are presented.     

碳纳米管修饰泡沫镍空气扩散电极电-Fenton法降解水中对硝基酚

采用涂覆焙烧法制备碳纳米管修饰泡沫镍空气扩散电极,并用环境扫描电子显微镜和循环伏安法对其表面形貌和氧化还原特性进行了表征。考察了该电极还原O2产生H2O2的性能及对水中对硝基酚的降解性能。表征结果表明:碳纳米管修饰泡沫镍空气扩散电极具有多级孔道结构;在-0.6 V处具有较强的氧双电子还原峰。实验结果表明:当电流为150 m A、反应时间为120 min时,产生的H2O2的质量浓度为321.38 mg/L;在外加0.1 mmol/L Fe SO4形成的电-Fenton体系中,反应30 min后对硝基酚去除率可达95.90%;且该电极重复使用10次的对硝基酚去除率为92%~96%。