Determination of the minimum ignition energy on the basis of a statistical approach

Based on existing MIE test results and new measurements, a statistical analysis for the MIE of hydrogen, ethene and propane is made by means of the logistic regression. The conditions necessary to carry out such an approach are discussed. It is shown that MIE values which are connected with a certain ignition probability could be determined adequately and lead to a more sophisticated result, also with regard to measurement uncertainties. This, in turn, leads to a better comparability and a higher informative content. At the same time, the MIEs of hydrogen, ethene and propane are reviewed. In doing so, a useful contribution to the discussion concerning the MIE of propane is made.     

Explosibility of micron- and nano-size titanium powders

Explosibility of micron- and nano-titanium was determined and compared according to explosion severity and likelihood using standard dust explosion equipment. ASTM methods were followed using a Siwek 20-L explosion chamber, MIKE 3 apparatus and BAM oven. The explosibility parameters investigated for both size ranges of titanium include explosion severity (maximum explosion pressure (P_max) and size-normalized maximum rate of pressure rise (K_St)) and explosion likelihood (minimum explosible concentration (MEC), minimum ignition energy (MIE) and minimum ignition temperature (MIT)). Titanium particle sizes were ?100 mesh (<150 μm), ?325 mesh (<45 μm), ≤20 μm, 150 nm, 60–80 nm, and 40–60 nm. The results show a significant increase in explosion severity as the particle size decreases from ?100 mesh with an apparent plateau being reached at ?325 mesh and ≤20 μm. Micron-size explosion severity could not be compared with that for nano-titanium due to pre-ignition of the nano-powder in the 20-L chamber. The likelihood of an explosion increases significantly as the particle size decreases into the nano range. Nano-titanium is very sensitive and can self-ignite under the appropriate conditions. The explosive properties of the nano-titanium can be suppressed by adding nano-titanium dioxide to the dust mixture. Safety precautions and procedures for the nano-titanium are also discussed.     

A Heart Rate Evaluation Approach to Determine Cost-Effectiveness an Ergonomics Intervention

This paper describes a hear-rate methodology to determine the cost-effectiveness of an ergonomics intervention to reduce workload and improve working conditions. This is a practical approach as opposed to the energy expenditure technique that is difficult to implement in natural settings. This was a laboratory study using a large excavator cabin with devices to simulate excavation operations. Mean heart rate was used to calculate the required rest time during a shift with or without air-conditioning. The criterion for evaluation was differences in required rest time during a shift under these 2 conditions. The simplicity and objectivity of this approach invites use to solve the problem of the economic evaluation of ergonomics interventions.     

硝酸异辛酯的热安全性研究

为了研究十六烷值改进剂—硝酸异辛酯(EHN)的热稳定性与热危险性,采用C600微型量热仪测试硝酸异辛酯的热分解特性.利用热分析技术考察温升速率对EHN热分解特性的影响,并利用活化能、TMRad(在绝热条件下最大反应速率到达时间)和自加速分解速率(SADT)方法评价此改进剂的危险性.结果表明,EHN发生分解反应的起始放热温度和最大放热温度均随着温升速率的增加而增大,且四种温升速率的反应机理是一致的.计算得到EHN热分解活化能在143.6-213.6kJ/mol之间.通过绝热条件下TMRad评价得出EHN在常温常压条件下不易发生危险失控,EHN自加速分解温度为98℃＞75℃,即在常温条件下储运是安全的,为储运硝酸异辛酯提供有力的数据支持.     

基于LCA方法评价多晶硅片生产的环境影响

多晶硅片制造是光伏产品生命周期过程中能耗及环境影响较大的环节之一.以四川某硅片企业一期(国内普遍水平)和二期(国内较先进水平)的实际生产数据为例,运用生命周期评价方法的分类、特征化、量化处理方法,定量计算单位多晶硅片生产的环境影响,计算结果显示:国内较先进水平比普遍水平提高了资源、能源的利用率,减少了污染物的环境排放,尤其表现在粉尘排放量、酸化潜值、全球变暖值和臭氧消耗潜值方面;并提出国内多晶硅片企业节能减排方法技术方法为利用清洁能源,提高循环水利用率,改进铸锭工艺,增大晶锭中晶粒的尺寸,改用环境污染物排放较少的硅片清洗原料.     

CNG站压缩机的节能优化改造

压缩机吸气压力低会造成压缩机运行效率低,影响CNG站能耗。通过对华油公司下属华阳鸿运（、NG站压缩机各级气缸的缸径进行改造,一级缸径qbl55ITIIn扩为Ф175mm,二级缸径Ф102mm扩为Ф105mm,三、四级缸径Ф78mm扩为Ф80mm。对比分析改造前后的压缩机排气量和耗电量,得出改造后压缩机实际产能同比增加42%、节电率最高可达31．5％的结论。改造后压缩机安全运行,283d即可收回改造费用。     

天然气净化厂脱硫装置能耗分析及节能措施探讨

高含硫天然气净化厂需对H2S含量较高的原料气进行处理,溶液循环量大、工艺流程长、公用工程消耗量大、能耗高。通过对天然气净化厂脱硫单元的耗能点及耗能关联因素进行分析,从优化工艺方案、采用先进节能设备、回收可回收的能量、减少工艺过程能量损失等方面,提出了热泵、贫液与半贫液分流工艺及板式换热器在MDEA脱硫单元中的应用及改造措施,详细阐述了各种节能措施的优势及适用条件。充分挖掘天然气净化厂的节能潜力,能够创造良好的经济效益和环境效益。     

基于PLC的电器能效测试系统设计

文章通过介绍一种基于PLC并符合GB 21519-2008要求的储水式热水器能效测试系统设计方案,研究PLC在电器能效测试的应用。该系统采用PLC作为下位机,控制电磁阀通断给所检测的样品供水和排水,通过读取能耗检测元件信号计算出能耗值,通过重量传感器输出量的变化换算得出储水式热水器的容积,利用温度模块测得样机各点的温度值;上位机采用PC机,利用组态软件,对现场实施监控与数据实时处理,通过友好的界面快速、实时、准确分析、计算、储存能效值。该系统的设计能有效地提高能效测试的可靠性和工作效率。     

气田增压机组烟气余热利用技术

综述国内外烟气余热利用技术的研究及应用现状,主要包括热能直接回收、吸收式制冷、有机朗肯循环和温差发电等方式。结合气田开采实际,分析讨论各类余热利用技术在气田增压机组烟气余热利用中的应用潜力和发展方向。在选择余热利用方案时,应结合气田增压机组现有条件、机组性能以及运行模式等因素进行综合评估。     

ACF吸附改良工艺在软包装复合生产中的应用

简介了软包装印刷工业复合生产过程中产生的VOCs污染物,探讨了现有ACF咐附回收有机溶剂设备存在的技术问题;结合软包装复合生产工艺特点,提出一种闭式循环的改良工艺,以解决能量浪费问题。