Consequence analysis of premixed flammable gas explosion occurring in pipe using a coupled fluid-structure-fracture approach

A coupled fluid-structure-fracture approach incorporating a high-efficiency detonation modeling algorithm was proposed to study the consequences of premixed flammable gas explosion occurring in pipe. A strain-rate-dependent failure criterion which is the vital prerequisite for accurate consequences prediction was derived based on the failure mechanism of materials at high strain rates and it was applied to account for the fracture of pipe. The simulated pressure time history and fracture patterns were validated against experimental results and good agreements were acquired. The interaction between detonation wave and pipe during crack extension, dynamic fracture processes of pipes with different initial flaws, venting features of detonation products and pressure profiles out of pipe were obtained and discussed in detail. The comparison with existing semi-empirical and CFD methods was performed and it is revealed that the deformation and fracture of pipe have obvious negative influences on the peak overpressure and the rate of pressure increase out of pipe. Because the energy absorption and dissipation due to structural deformation and fracture are well taken into account, the coupled fluid-structure-fracture method is expected to provide more rational consequences prediction and analysis results.     

Consequence modeling of a real rupture of toluene storage tank

Chemicals used in paint industry are generally comprised of toxic and inflammable substances; they may cause serious problems for humans and environment if safety conditions are neglected. In 2012, rupture of a toluene tank in a paint factory in Iran claimed lives of two workers near the tank. The present study is formulated in order to model the incident. The results showed the area prone to flash fire occurrence and extension. Furthermore, radiation was measured in terms of distance to the tank. A bund wall is also assumed around the vessel in order to determine its influence on evaporation in flash fire area, radiation, and maximum concentration of vapor cloud. The results provided important hints on minimum and required distance of electrical equipment or electrical enclosure (PLC) installation from vessels as well as suitable distance between the vessels. Finally, preventive recommendations were proposed to reduce the risk of potential accidents.     

CNG汽车加气站火灾爆炸危险分析与预防

对压缩天然气（CNG）汽车加气站的危险因素进行了辨识，并且用事故树法对加气站的火灾爆炸危险进行了分析，从技术、教育、管理3个方面提出了预防控制措施。     

粉碎研磨设备粉尘爆炸的预防

粉碎研磨设备火灾爆炸事故发生率较高。针对该过程的火险特点,防火对策应从防止粉尘沉积,消除粉尘源,防止摩擦、撞击、生热,消除静电危害,搞好工艺防火,惰性介质保护,设置防爆泄压装置,粉尘爆炸的抑制,火灾事故处理措施,加强消防安全教育诸方面加以考虑。     

多孔填充材料的防火防爆机理及应用

在液化气体、燃料储罐内填充多孔材料,可有效地减少或避免储罐发生爆炸事故.本文分析了这类材料的防爆机理并简要介绍了其应用情况.     

液化天然气储罐火灾爆炸事故的定量分析

介绍了某天然气站的基本情况,利用道化学指数评价法,对该站储罐区的1个3000m3球罐进行风险评价,评价结果表明：该罐火灾爆炸指数为149.1,危险等级是较大。一旦罐内天然气在储存过程中发生火灾、爆炸,将使半径38.17m内,面积4574.82m2内的设备、设施受到损害,最大可能财产损失为0.66A万元。由于罐区采取了一些安全措施对储罐安全进行补偿,有效地降低了事故损失。为操作管理者更加全面地了解整个罐区的风险状况提供参考,有利于天然气储罐区的规划、管理及事故预防等。     

静电喷漆作业的防火防爆

静电喷漆工艺应用普及很快,但其生产过程的火灾危险性属甲类。其火灾危险主要在于使用的漆料或有机溶剂,喷漆作业中存在电火花、静电火花、高温热表面、自然发热等引火源。为防止火灾爆炸发生,要注重防火防爆安全管理和强化必要的安全技术措施。     

基于改进贝叶斯网络的加油站火灾爆炸分析

为了找出导致加油站发生火灾爆炸事故的基本事件及其可能性大小,以加油站火灾爆炸故障树为基础建立相应的贝叶斯网络风险模型。在FTA向BN转化算法的基础上对条件概率做出了修正。利用GeNIe软件计算加油站火灾爆炸事故基事件的后验概率,同时进行灵敏度和影响力分析。最后通过实例分析,找出了导致某加油站发生火灾爆炸事故危险性最大的因素集为:加油站接打手机、机械碰撞、给塑料容器加油、加油冒油、油枪渗漏等。结果表明,注重基事件的多态性和事件间逻辑关系合理性的新模型,能推算出更准确的基事件概率分布,同时可以找出导致事故发生的最有可能途径,为加油站事故预防,系统改进提供较为合理性建议。     

Gas leakage consequence modeling for buried gas pipelines

One of conservation transfer methods for such widely-used gases as natural gas and hydrogen is buried pipelines. Safety of these pipelines is of great importance due to potential risks posed by inefficiencies of the pipelines. Therefore, an accurate understanding of release and movement characteristics of the leaked gas, i.e. distribution and speed within soil, the release to the ground surface, the movement of hydrogen gas through the ground, gas underground diffusion, gas dispersion in atmosphere, and following consequences, are very important in order to determine underground dispersion risks. In the present study, consequences of gas leakage within soil were evaluated in two sub-models, i.e. near-field and far-field, and a comprehensive model was proposed in order to ensure safety of buried gas supply pipelines. Near-field model which is related to soil and ground and its output is the gas released at different points and times from ground surface and it was adopted as input of far-field sub-model which is dispersion model in atmosphere or an open space under the surface. Validation of near-field sub-model was performed by the experimental data obtained by Okamoto et al. (2014) on full-scale hydrogen leakage and then, possible scenarios for far-field sub-model were determined.     

Safety analysis of instantaneous release of compressed natural gas from a cylinder

This study presents a numerical model to analyze the sudden failure of compressed natural gas (CNG) cylinder onboard a CNG vehicle. The model is developed using COMSOL. It accounts for the real gas effects, physical energy, and combustion of the flammable gas. The model is tested using experimental data.The study highlight compression energy as one of the serious concern. An unintentional rupture of a compressed cylinder filled with natural gas would generate a rapid energy release in the form of the pressure energy (blast). The release of energy and gas would cause rapid mixing and generate overpressure and may also cause flash fire. A detailed failure frequency analysis is also done to analyze the effectiveness of barriers. This study identifies critical points for the safe operation of the CNG system onboard a vehicle.     

煤矿瓦斯爆炸事故的防治对策

我国煤矿日趋严重的瓦斯爆炸事故灾害严重地威胁着矿井工作人员的生命安全，制约矿井生产的发展，给煤炭企业带来沉重的负担，从安全科学的角度及其事故原因分类出发，提出了防治我国煤矿瓦斯爆炸事故的对策。     

Accident modeling of toxic gas-containing flammable gas release and explosion on an offshore platform

Toxic gas-containing flammable gas leak can lead to poisoning accidents as well as explosion accidents once the ignition source appears. Many attempts have been made to evaluate and mitigate the adverse effects of these accidents. All these efforts are instructive and valuable for risk assessment and risk management towards the poisoning effect and explosion effect. However, these analyses assessed the poisoning effect and explosion effect separately, ignoring that these two kinds of hazard effects may happen simultaneously. Accordingly, an integrated methodology is proposed to evaluate the consequences of toxic gas-containing flammable gas leakage and explosion accident, in which a risk-based concept and the grid-based concept are adopted to combine the effects. The approach is applied to a hypothetical accident scenario concerning an H₂S-containing natural gas leakage and explosion accident on an offshore platform. The dispersion behavior and accumulation characteristics of released gas as well as the subsequent vapor cloud explosion (VCE) are modeled by Computational Fluid Dynamics (CFD) code Flame Acceleration Simulator (FLACS). This approach is concise and efficient for practical engineering applications. And it helps to develop safety measures and improve the emergency response plan.     

对锦州石化公司催化裂化装置火灾爆炸危险性的评价

根据美国道化学公司的火灾爆炸危险度评价原理,采用单元危险快速排序法,对锦州石化公司的催化裂化装置的火灾爆炸危险性进行综合评价。     

液化石油气爆炸范围及爆炸力的测定

液化石油气、瓦斯等可燃气体的爆炸防治是一个非常迫切需要解决的问题.利用自制可燃气体爆炸箱来模拟可燃气体爆炸,并通过光干涉甲烷测定仪来测定混合气体爆炸时的甲烷百分含量,再推算出液化石油气的爆炸范围和计算爆炸力.     

密闭空间内天然气混合及爆炸传播规律研究

为研究密闭容器内甲烷-空气不均匀分布对混合气体燃烧的影响,将数值模拟和实验相结合,发现在重力作用下混合气体浓度分布不均匀,长径比越大的容器,混合气体浓度分布梯度越大。混合气体浓度分布影响气体火焰传播规律。宏观浓度为5%的甲烷与空气混合后,容器上部甲烷浓度高于5%,在该处点火时非均匀混合甲烷-空气火焰传播较快,非均匀混合气体的爆炸压力比均匀混合气体压力上升快,且分层混合气体的超压峰值高于均匀混合气体的值。由于浓度分布不均匀,点火位置影响甲烷/空气火焰传播的规律。     

密闭空间燃气泄漏爆炸危险区域迁移规律

为了给室内燃气泄漏爆炸事故的预防和事故后果评价提供理论依据,借助计算流体力学技术,对密闭空间内燃气泄漏扩散的非稳态流场进行了数值模拟,着重考察了燃气爆炸危险区域随时间和空间的分布特征。研究结果表明,在泄漏初始阶段,爆炸危险区域位于泄漏源上部。随着泄漏和扩散的持续发展,爆炸危险区域整体下移,最终迁移至地面附近。爆炸危险区域范围随时间由小变大,再由大变小。爆炸危险区域在房间下部的持续时间明显长于房间中上部。     

井喷点火过程天然气爆炸后果分析

井喷失控事故发生后，尽快点火是减少人员伤亡的最有效措施之一。然而，点火过程中一旦发生天然气爆炸，其可能的爆炸伤害范围、破坏范围以及是否在可接受风险范围，就成为决策能否点火的关键。本文应用蒸汽云爆炸的肿当量模型和冲击波峰值超压模型，提出了天然气井喷失控后，发生天然气爆炸的人员死亡区、重伤区和轻伤区的计算方法；假设井喷的天然气无阻流量，计算了可能的人员伤害范围，并对计算结果进行了分析。分析发现，在井喷失控后，最大限度地减少井喷失控时间，以及最大限度地防止天然气在某一区域的大量积聚，是减轻井喷失控天然气爆炸后果的最佳措施。     

Case study on the catastrophic explosion of a chemical plant for production of m-phenylenediamine

On March 21, in Xiangshui County, Yancheng city, China, a catastrophic explosion occurred at Tianjiayi Chemical Co., Ltd. that caused 78 deaths and injured more than 617 individuals, with a property loss of as much as US$ 100 million. An explosion crater with a diameter of 98 m was generated. An extensive consequence analysis based on the crater size and physical effects for the estimation of the quantity of exploded dinitrobenzene (DNB) was performed. By using the position recorded in the satellite photo and the layout of the plant, the crater site was determined to be located near a warehouse where dinitrobenzene was stored. From the scaling law associating the TNT equivalent with crater diameter, the TNT equivalent of exploded ditrobenzene was determined to be approximately 708 tons. Based on the results of the consequence analysis performed by three methodologies, it can be concluded that the Tianjiayi Chemical Co. warehouse not only stored a substantially large quantity of dinitrobenzene but was also located too close to adjacent structures without an adequate separation distance. Judging by the effect of explosive blast on personnel, a fatality radius was determined to be about 400 m from the explosion center.     

天然气管道泄漏爆炸实验分析

天然气管道失效造成泄漏爆炸给周围人员带来非常严重的危害,对其危害范围的研究对输气管道设计和运行具有重要的意义。常见的天然气管道泄漏爆炸伤害半径计算方法有蒸气云爆炸(VCE)定量评价模型、TNO多能法评价模型、API pub 581定量后果评价模型和炸药爆炸经验公式。为验证不同评价模型在受限空间的预测效果,利用天然气爆炸试验台进行了受限空间爆炸实验,得到最大压强与距离经验关系,计算出天然气浓度为7%、9%和11%情况下爆炸死亡半径。计算结果与不同经验模型预测结果比较,表明当天然气浓度为7%~11%时,蒸气云爆炸(VCE)定量评价模型和炸药爆炸经验模型与实验结果最为接近,误差分别为-113%和189%,TNO多能法评价模型和API pub 581定量后果评价模型预测结果偏小。结论对有限空间天然气管道爆炸研究具有实际意义。     

矿井防爆门、盖自动封堵装置研发

煤矿井底发生煤尘瓦斯爆炸事故时产生的冲击波会冲开风井防爆门、盖,引起主风机风流短路,井底风流紊乱、通风系统瘫痪,导致毒害气体扩散、瓦斯积聚,引发二次爆炸。为了减少因此造成的损失,研发了一种在防爆门、盖被摧毁后能自动封堵的装置,通过感应防爆门盖的损毁信号控制充气动力设备对气囊折叠体进行充气,折叠体被充气弹出储藏硐室,沿支撑架构延展、膨胀并充满井筒横截面,实施对风井的密封,以维持灾后井底持续通风,降低灾害后果,为井底幸存人员的生存与自救提供有利条件。