Flammability hazard analysis of imidazolium-based ionic liquid binary mixtures under high temperatures

Ionic liquid (IL) mixtures are promising because they can optimize the involved properties according to industrial needs. It has already been demonstrated that IL flammability is due mainly to IL decomposition generating flammable substances. Four different ILs, 1-Butylimidazolium tetrafluoroborate ([BIM][BF₄]), 1-butylimidazolium nitrate ([BIM][NO₃]), 1-butyl-3-methylimidazolium tetrafluoroborate([BMIM][BF₄]), and 1-butyl-3-methylimidazolium nitrate ([BMIM][NO₃]), were selected as the parent salts to form the different imidazolium-based IL binary mixtures. These mixtures were tested via isothermal thermogravimetric analyzer (TGA) at different temperatures (120, 150, 180, 210, and 240 °C), then tested by the flash point analyzer after isothermal heating pretreatment at the above temperatures. Results show that the mixtures' flash point values decrease with the heating temperature increase. Vaporization of the IL mixtures’ decomposition products results in a higher concentration of flammable gases and a flash point decrease, which lead to the flammability hazard increasing. Moreover, results show that the flash points of the studied binary imidazolium IL mixtures are more similar to those of the more unstable IL in their parent ILs. Also, the flammability hazard of IL binary mixtures may obviously increase under the high temperature environment for a long time.     

Reaction hazard and mechanism study of H2O2 oxidation of 2-butanol to methyl ethyl ketone using DSC,Phi-TEC II and GC-MS

Methyl ethyl ketone (MEK) oxidation via H₂O₂ with tungsten-based polyoxometalate catalysts has gained much attention with an ever-growing body of knowledge focusing on the development of environmentally benign processes in chemical industry. In this study, two calorimetry techniques, differential scanning calorimetry (DSC) and Phi-TEC II adiabatic calorimetry, were employed to analyze the thermal hazards associated with the 2-butanol oxidation reaction system. Hydrogen peroxide was the oxidant and a tungsten-based polyoxometalate as the catalyst. Gas chromatography-mass spectrometry was used for identification of the organic products. Important thermal kinetic data were obtained including “onset” temperature, heat of reaction, adiabatic temperature rise and self-heat rate. From DSC results, three exothermic peaks were detected with a total heat generation of approximately 1.26 kJ/g sufficiently to induce a thermal runaway. Possible reaction pathway for three stages were proposed based on both DSC and GC-MS results. One exotherm was detected by Phi-TEC II calorimeter and the pressure versus temperature profile together with the DSC and GC-MS data demonstrate the complexity of 2-butanol reaction system under both thermal screening and adiabatic conditions.     

基于疲劳原理探究超(超)临界电站锅炉减温器失效模式

本文总结介绍了常见炉型超(超)临界电站锅炉减温器的布置方式和结构形式,并以上海锅炉厂生产的SG-3005/29.3-M7008型超超临界锅炉再热器微量喷水减温器为例,基于水汽温差作用下产生的热疲劳和蒸汽高速冲刷产生的机械振动疲劳原理,探究总结了喷水减温器的失效模式,并提出了设计、制造安装、运行及检验建议.     

基于GIS的城市特大火灾蔓延模拟

本文将对城市特大火灾的蔓延机理进行深入剖析,并构建火灾蔓延的半经验半理论模型。该模型包括两个子模型,其一为个体建筑火灾发展的简化模型,其二为建筑物间的火灾蔓延模型。前者简化了个体建筑内部火灾发展与蔓延的复杂过程,仅简单评价了个体建筑火灾发展所处的阶段,即起火、轰燃、充分发展与倒塌,并计算出各阶段相应的物理量。后者则是从建筑物间火灾蔓延的机理入手,借鉴已有模型对两种主要的火灾蔓延方式热辐射与热对流进行模型的简化和修正,并且量化了影响建筑物间火灾蔓延的气象条件。最后,作者提供了基于GIS的城市特大火灾蔓延模拟方案,并将模拟方案用于对日本1995年阪神地震后神户市高桥医院周边一处起火进行火灾蔓延模拟,再将模拟结果与实际火灾蔓延结果进行对比,从对比中充分体现出模型的有效性。     

关于火电厂验收存在的问题分析

对火电厂中以煤、天然气、油或焦油、秸秆为原料时验收监测应注意的问题进行了分析和探讨。重点提出了烟气脱硫、Hg、As、氟化物的污染以及多环芳烃、二的产生和以后环评、环评批复及验收监测中应注意的问题。     

模组箱体空间内磷酸铁锂电池热失控及其传播行为研究

为了探究储能用锂离子电池在真实应用场景下的热失控及其传播行为特征,选用86 Ah方形磷酸铁锂(LiFePO₄)电池,对其在热滥用触发方式下的热失控行为及模组箱体空间与开放空间中的传播行为规律进行了实验研究。单体实验结果表明,电池热失控产生的高温烟气会导致模组箱体内沿高度方向出现明显温度梯度,模组底部与顶部温度测点的最大温差达118.4℃。传播实验结果表明,模组箱体空间内热失控电池通过产气及喷出高温电解液向其他电池传热,在热失控电池影响下,模组箱体空间内3块电池上表面所能达到的最高温度均高于开放空间实验12℃～150℃,模组空间内热失控电池向同侧两块电池的传热量高于开放空间实验225 kJ和44.4 kJ。但箱体环境中有限的氧气供给会减缓电池在热失控时的内部放热反应进程,模组箱体空间实验中电池热失控峰值温度较开放空间实验低33℃～145℃,并且模组箱体空间实验中热失控完全传播所用时间较开放空间实验滞后213 s。研究结果对于锂离子电池模组的安全设计和热失控传播阻隔具有一定的参考价值与指导意义。     

新型难燃隔热保温材料——酚醛泡沫

本文介绍了一种新型难燃隔热保温材料-酚醛泡沫塑料,它具有有机泡沫保温材料低热导率的优异性能,也具有无机保温材料优异的防火性能.     

Effect of incineration on the removal of key offensive odorants released from a landfill leachate treatment station (LLTS)

As a basic means to control odorants released from a landfill leachate treatment station (LLTS), effluents venting from this station were treated via incineration with methane rich landfill gas (at 750 °C). A list of the key offensive odorants covering 22 chemicals was measured by collecting those gas samples both before and after the treatment. Upon incineration, the concentration levels of most odorants decreased drastically below threshold levels. The sum of odorant intensities (SOIs), if compared between before and after incineration, decreased from 6.94 (intolerable level) to 3.45 (distinct level). The results indicate that the thermal incineration method can be used as a highly efficient tool to remove most common odorants (e.g., reduced sulfur species), while it is not so for certain volatile species (e.g., carbonyls, fatty acids, etc.).     

PESTICIDE RESIDUES IN THERMAL MINERAL WATER IN GREECE

Eight different hot springs (SPA) in Greece were monitored over a one-year survey for priority pesticide residues. A specific and effective procedure including solid phase extraction in combination with HPLC and GC analytical methods were applied. Samples that were sensitive to nitrogen-phosphorus (NPD) and/or electron capture (ECD) detectors were analysed by capillary gas chromatography.

From the twenty-six water samples, pesticide residues were detected in fourteen of them (54%) but no one exceeding the European Union Maximum Acceptable Concentration (MAC).

Lindane (γ-BHC) was the most frequently detected pesticide. It was found in nine samples (35%) in concentrations from <0.005 to 0.01 μg/L. Other pesticides detected were phorate (in five samples), propachlor (in two samples) and chlorpyriphos ethyl (in three samples) but in concentrations far below the permissible levels.     

Improving anaerobic sewage sludge digestion by implementation of a hyper-thermophilic prehydrolysis step

The present study focuses on a two-step process for treatment and stabilisation of primary sludge. The process consists of a hyper-thermophilic hydrolysis step operated at 70 degrees C and a hydraulic retention time (HRT) of 2 days followed by a thermophilic (55 degrees C) anaerobic digestion step at a HRT of 13 days. A one-step anaerobic digester operated at 55 degrees C and 15 days HRT was used as a reference process. The two-step process was characterized by a 12% higher organic suspended solids removal efficiency and better pathogen reduction effect than the conventional one-step digestion. The microbial community of the digester fed with pre-treated sludge was characterised by a higher activity compared to that of the digester treating raw sludge. Moreover, the pre-treatment of the primary sludge resulted up to 48% increase of the methane potential (20.09 and 13.56mmolCH(4)g(-)VS(-1) with and without pre-treatment, respectively) and up to 115% increase of the methane production rate. Finally it was shown that the extra energy requirements for the operation of a pre-treatment step would be covered by the energy produced from the extra methane production and in addition there would be a significant energy surplus of 2.17kJd(-1) for the system tested.