试论ISO11014-1应增设有关理化参数

提出了在执行国际标准ＩＳＯ１１０１４－ １ 即化学品安全技术说明书的数据模式中应增设可燃液体的燃烧速率、比热和蒸发潜热等理化参数,并阐述了增设的必要性、作用、对策及建议。     

Validation of the UN test method N.5

Many substances react with water in such a way that flammable gases are formed. For transport issues this reaction may possess a considerable hazard especially if the cargo is wetted by rain or by water from other sources. In the UN Recommendations on the Transport of Dangerous Goods these kinds of problems are addressed. The UN test N.5 “Test method for substances which in contact with water emit flammable gases” corresponds to this hazard. Classification according to the test method is done by measurement of the gas evolution rate of the flammable gas by any suitable procedure. At BAM a gravimetric approach is used to measure the gas evolution rate. In this paper we present the evaluation of the apparatus by means of an absolute calibration routine utilizing a reaction where a known amount of gas is produced as well as the evaluation of important parameters influencing the gas evolution rate using different substances. It can be shown that the apparatus is capable of measuring absolute gas volumes as low as 6 mL with an acceptable error of about 17% as determined from the reaction of Mg with demineralized water.     

Towards the development of a multidisciplinary understanding of the effects of toxic chemical mixtures on health

Mixtures can be divided into simple (chemicals with comparable properties—health risk assessments on the chemicals) and complex, which can be further subdivided into defined (a reasonably distinct composition, created at a specific time and place despite dissimilar components—risk assessments on the common source) and coincidental (chemicals without similar properties or constant composition in time or space—risk assessments on the receptor). Interactions recognized are: independent action, dose addition (additivity), and potentiation (synergy and antagonism). Unpredicted outcomes need recognition. New approaches in higher education and multidisciplinary investigations are essential. The community of the Society for Environmental Geochemistry and Health should help clarify points such as when transformations in mixtures may become important enough to alter the classification and the risk assessment. The multidisciplinary community is also well placed to support the integration of nonchemical influences into mixture analysis and to contribute to the investigation of cumulative and multiple exposures.     

Experimental investigation of the complex deflagration phenomena of hybrid mixtures of activated carbon dust/hydrogen/air

This paper aims to develop quantitative insights based on measured deflagration parameters of hybrid mixtures of activated carbon (AC) dust and hydrogen (H₂) gas in air. The generated experimental evidence is used to reject the claim of the null hypothesis (H₀) that severity of deflagrations of H₂/air mixtures always bound the severity of deflagrations of heterogenous combustible mixtures of AC dust/H₂/air containing the same H₂ concentrations as in the H₂/air binaries. The core insights of this investigation show that the maximum deflagration pressure rise (ΔP_MAX) and maximum rate of pressure rise ((dP/dt)_MAX) of this hybrid mixture are greater than those corresponding to deflagrations of H₂/air mixtures for all the dust and H₂ concentrations being examined. The deflagration severity indices (K_St and ES) of the hybrid mixture containing 29 mol% H₂ are found to be greater than those of the H₂/air mixture containing 29 mol% H₂. Also, the minimum explosible concentration (MEC) of the hybrid mixture is lower than that of the AC dust in air only. The insights gained should lead to better realization of the severity of a postulated safety-significant accident scenario associated with on-board cryoadsorption H₂ storage systems for fuel-cell (FC) powered light-duty vehicles. The identified insights could also be relevant to other industrial processes where combustible dusts are generated in the vicinity of solvent vapors. Moreover, these insights should be useful for supporting quantitative risk assessment (QRA) of on-board H₂ storage systems, designing improved safety measures for cryoadsorption H₂ storage tanks, and guiding H₂ safety standards and transportation regulations.     

构建三元混合污染物的三维等效图

等效线分析法广泛应用于二元混合物的毒性相互作用评估.然而,如何构建三维等效图以考察三元混合物中发生的毒性相互作用至今没有文献报道.本研究的主要目的即以三元混合物中3个组分的相对浓度为坐标轴建立三维等效图以考察三元混合物的毒性相互作用.以6种目前在中国广泛使用的农药,包括3种除草剂(2,4-D、敌草净、西草净)和3种杀虫剂(乐果、吡虫啉、残杀威)为混合物组分,采用均匀设计射线法(UD-Ray)分别对三元除草剂和三元杀虫剂混合物中各组分浓度分布进行优化设计,以全面表征实际混合物的浓度多样性.通过费氏弧菌微板毒性分析法测定农药及其三元混合物在不同浓度下的发光抑制毒性,以浓度加和(CA)模型为加和参考模型,建立三维等效图,分析各混合物的毒性相互作用.结果表明,三维等效图能清晰、直观地反映三元混合物的毒性相互作用信息,开拓等效分析法在三元混合物毒性分析中的应用.     

Minimum ignition energy of mixtures of combustible dusts

Most industrial powder processes handle mixtures of various flammable powders. Consequently, hazard evaluation leads to a reduction of the disaster damage that arises from dust explosions. Determining the minimum ignition energy (MIE) of flammable mixtures is critical for identifying possibility of accidental hazard in industry. The aim of this work is to measure the critical ignition energy of different kinds of pure dusts with various particle sizes as well as mixtures thereof.The results show that even the addition of a modest amount of a highly flammable powder to a less combustible powder has a significant impact on the MIE. The MIE varies considerably when the fraction of the highly flammable powder exceeds 20%. For dust mixtures consisting of combustible dusts, the relationship between the ignition energy of the mixture and the minimum ignition energy of the components follows the so-called harmonic model based upon the volume fraction of the pure dusts in the mixture. This correlation provides results which show satisfactory agreement with the experimental values.     

Fire accident investigation of an explosion caused by static electricity in a propylene plant

This study investigated a 2010 fire and explosion that occurred at a polypropylene (PP) and copper-clad laminate high-tech plant in Taiwan. Liquid acetone leakage caused the fire and explosion. One person was killed and five were injured; property damage was estimated at US$20 million. In contrast to conventional plants, high-tech plants have sophisticated instrumentation, highly complex pipelines, and confined spaces. In addition, the floor area in a high-tech plant is large and frequently contains a channel through the ground floor to the second or third floor. This channel design enables the fire compartment to be destroyed. Therefore, the system cannot confine the fire to a specific area, thus hindering fire-relief operations. In this study, the original fire outbreak occurred in the PP processing area on the ground floor. The acetone storage tank was located on the third floor. The investigation conducted at the fire site of the situations of the burning (bursting) loss determined that the acetone liquid leaked and dripped from floor cracks and tunnel oven to the PP processing area. Because the PP manufacturing process rapidly generates static electricity, the flammable liquids made contact with the source of ignition, which caused the explosion and fire. Various procedures, such as those involving the operating environment of production, packaging, and processing in a high-tech plant, are likely to produce static electricity in a workplace. Improved electrostatic management can prevent the loss of property and lives, liquid acetone leakage, and loss of equipment caused by static electricity fire.     

半密闭空间油气爆炸初期火焰特性研究

为了研究半密闭空间内部油气着火爆炸初期火焰特性,进行了不同油气体积分数下的油气着火爆炸实验,通过高速摄影等技术手段对爆炸过程中火焰形态进行了捕捉,分析了不同油气体积分数下爆炸初期火焰着火模式、火焰形态、传播过程和火焰浮力稳定性的变化规律。结果表明:油气体积分数为决定容器内部着火模式的关键因素,随着油气体积分数的逐渐增大,着火模式呈现出燃烧-爆炸-爆燃后持续燃烧的转变;爆炸下的火焰具有明显的分区现象,而其他的着火模式则没有;随着油气体积分数的增加,越靠近化学当量比,纵向和横向火焰阵面速度越大;油气体积分数小于等于1.1%或大于等于2.6%时,火焰稳定性受浮力影响显著。     

Transfer of powders into flammable solvents overview of explosion hazards and preventive measures

This paper evaluates and analyses the explosion hazards associated with transfer operations of powders into large containers, hoppers and reactors, which may also contain flammable solvent vapours. The formation and characteristics of explosive atmospheres and the occurrence of process inherent ignition sources, such as static electricity are described. The most commonly applied preventive measures and technical equipment are outlined and discussed including their advantages and disadvantages.     

Fire and risk analysis during loading and unloading operation in liquefied petroleum gas (LPG) bottling plant

The article focuses on analyzing risks associated with the gas transfer operation in a liquified petroleum gas (LPG) bottling plant in India. The transfer operations involve transferring liquified gas from the transport tanker to the underground storage tank. Due to the rapid expansion of the cities, many LPG bottling plants in India got surrounded by residential areas and business centers. Moreover, to maintain the supply chain, the frequency of the transfer operations at the bottling plant also increased. In this scenario, an accidental release of LPG during the transfer operation may lead to various consequences such as a pool fire, a fireball, and even a catastrophic rupture of the tank with a successive explosion of its contents. In the study, the operations involved in bottling plants are classified into different hazard zones and analyzed. The probability of occurrence of events leading to an accident is modeled using modeling tools such as ALOHA and PHAST. The consequences of an accident following various events, such as jet fire, fireball, etc., are modeled, and the simulation results are compared. The thermal radiation has been estimated as 4–40 kW/m², which could adversely affect the nearby population and could result in damaging plant machinery and equipment.