大型原油储罐泄漏隔堤池火灾后果研究

为了研究储罐大孔泄漏后可能产生的隔堤局部面状液池火灾,以10万立方大型原油储罐为例,采用计算流体力学软件FLUENT和火灾模拟软件FDS计算储罐在真实泄漏场景下的液池区域,模拟发生隔堤池火的分布特征及对临罐热辐射影响。研究结果表明:储罐原油泄漏后将在隔堤内形成相对稳定面积的液池,在储罐不同方位处泄漏形成的液池面积与储罐壁距雨水收集槽长度相关;储罐正下方的隔堤池火对储罐造成的热辐射极大;风对临罐受到的池火热辐射强度影响明显,指向罐组中心方向的来风对临罐热辐射强度影响较大。     

基于蒙特卡洛法的储罐爆炸碎片冲击失效模型研究

为定量研究相邻储罐间爆炸碎片冲击的多米诺效应,基于蒙特卡洛方法建立爆炸碎片冲击失效模型。该模型共包括爆炸能量与碎片初始速度、考虑风速及碎片初始位置的碎片三维抛射轨迹、空气阻力、碎片冲击穿透等4个分步模型。基于上述模型,研究储罐爆炸后碎片的初始状态、抛射轨迹以及对相邻储罐的冲击效应。在数值模拟结果的基础上,用储罐最高允许工作压力代替泄放装置的泄压压力来计算爆炸压力,绘制碎片质量及初始速度的直方图,定量分析储罐间距对击中概率的影响。结果表明,热辐射、超压和碎片冲击3种能量作用方式均可能导致储罐间火灾爆炸事故多米诺现象发生,但爆炸碎片冲击导致相邻罐失效的概率较低。     

Improved models of failure time for atmospheric tanks under the coupling effect of multiple pool fires

Fire accidents of chemical installations may cause domino effects in atmospheric tank farms, where a large amount of hazardous substances are stored or processed. Pool fire is a major form of fire accidents, and the thermal radiation from pool fire is the primary hazard of domino accidents. The coupling of multiple pool fires is a realistic and important accident phenomenon that enhances the propagation of domino accidents. However, previous research has mostly focused on the escalation of domino accidents induced by a single pool fire. To overcome the drawback, in this study, the failure of a storage tank under the coupling effect of multiple pool fires was studied in view of spatial and temporal synergistic process. The historical accident statistics indicated that the accident scenario of two-pool fires accounted for 30.6% in pool fires. The domino accident scenario involving three tanks is analyzed, and the typical layout of tanks is isosceles right triangle based on Chinese standard “GB50341-2014”. The thermal response and damage of a target tank heated by pool fires were numerically investigated. The volume of 500 m³, 3000 m³, 5000 m³ and 10000 m³ were selected. Flame temperature was obtained by FDS, and then was input onto the finite element model. The temperature field and stress field of target tanks were simulated by ABAQUS. The results showed that the temperature rise rate of the target tanks under multiple pool fires was higher than that under a single pool fire. The failure time of the tank under the coupling effect of multiple fires was lower than that under the superposition of multiple fires without the first stage. The stress and yield strength were compared to judge the failure of the target tank. The model of failure time for the tank under the coupling effect of pool fires was established. Through the verification, the deviation of this model is 4.02%, which is better than the deviation of 15.76% with Cozzani's model.     

埋地油罐事故伤害范围模拟评价

分析埋地油罐可能发生的火灾爆炸事故,建立事故模拟模型,模拟爆炸物质完全燃烧的质量依据化学计量浓度确定,事故伤害范围的计算用G.M莱克霍夫在砂质土壤中爆炸的冲击波计算方法。对50 m3埋地油罐模拟,油蒸气形成爆炸性混合气体爆炸伤害范围较大,安全范围与《汽车加油加气站设计与施工规范》中相关规定相符合。模拟方法用于埋地储罐的定量安全评价,为罐区选址、建设、安全距离确定及安全预案制定提供参考。     

Study of the situation deduction of a domino accident caused by overpressure in LPG storage tank area

The production and storage of liquefied petroleum gas (LPG) is gradually becoming larger and more intensive, which greatly increases the risk of the domino effect of an explosion accident in a storage tank area while improving production and management efficiency. This paper describes the construction of the domino effect scene of an explosion accident in an LPG storage tank area, the analysis of the characteristics of the LPG tank explosion shock wave and the target storage tank failure, and the creation of an ANSYS numerical model to derive the development trend and expansion law of the domino accident in the LPG storage tank area. The research showed that: 400 m³ tank T1 explosion shock waves spread to T2, T4, T5, T3, and T6, and the tank overpressures of 303 kPa, 303 kPa, 172 kPa, 81 kPa, and 61 kPa respectively. The critical values of the target storage tank failure overpressure-range threshold were 70 kPa and 60 m. After the explosion of the initial unit T1 tank, at 38 ms, the T2 and T4 storage tanks failed and exploded; at 56 ms, the T5 storage tank exploded for the third time; at 82 ms, the T3 storage tank exploded for the fourth time; and at 102 ms, the T6 storage tank exploded for the fifth time. With the increase of explosion sources, the failure overpressure of the target storage tank increased, and the interval between explosions continuously shortened, which reflected the expansion effect of the domino accident. The domino accident situation deduction in the LPG storage tank area provided a scientific basis for the safety layout, accident prevention and control, emergency rescue, and management of a chemical industry park.     

Scenario deduction of Natech accident based on dynamic Bayesian network: A case study of landslide accident in a liquor storage tank area in Guizhou Province,China

Industrial technical accidents caused by natural disasters are defined as Natech accidents, such as earthquakes and landslides, which can cause tremendous damage to industrial storage tanks, and lead to accidental leakage and even serious fire and explosion accidents. In this study, a landslide-induced storage tank accident model under earthquake disasters was proposed, and the relationship between landslide mass impact and target impact resistance was taken into account. Also, tank failure and the formation of the pool fire were considered to be the consequences of the Natech accident. Through scenario deduction, the dynamic process of landslide Natech was transformed qualitatively into a disaster chain network diagram composed of a scenario state, a disaster-causing factor and emergency management. The Bayesian network was used to learn and deduce the parameters of the network diagram, and in this process, the prior probability and conditional probability of nodes were obtained primarily by Monte Carlo simulation, and by an improved expert scoring method based on the fuzzy set theory. Through visualization software, the sensitivity analysis of landslide Natech was achieved. Finally, a case study of a liquor storage tank area in Guizhou Province, China was carried out, and the results show that a large amount of hazardous material leakage caused by buckling is key to the formation of pool fire accidents, and several prevention measures for earthquake-induced landslide Natech was proposed according to the sensitivity analysis.     

氨分解装置中液氨储罐火灾爆炸危险性分析

以某金属处理企业氨分解装置中液氨储罐罐区为例,对液氨泄漏后火灾爆炸事故及其伤害范围进行了研究,用池火、蒸气云爆炸和沸腾液体扩展蒸气爆炸模型进行计算分析,给出火灾、爆炸事故的人员伤害和财产损失范围。结果表明:围堤堤内池火或罐内池火时,罐区建构筑物内的汽化器、管道等设备会因直接过火或热辐射导致损坏,建筑内人员死亡,但难以波及罐区之外;蒸气云爆炸产生相当于1192.72kgTNT爆炸的当量,爆炸的后果严重,应重点防范,防范的重点为液氨泄漏、点火源;沸腾液体扩展蒸气爆炸的火球半径56.1m,持续时间8.7s,死亡半径27.2m,其源于储罐受热或系统突然失效,液体瞬时泄漏汽化并遇点火源而发生,具有突发性且后果严重,企业应高度重视并严格储罐及系统的定期检验与校验、密切关注系统的有效运行。     

大型原油商业储备油库火灾危险性数值模拟分析

石油储备油库多向大型化、复杂化方向发展,发生事故时扑救非常困难。为了深入探讨巨型油罐火灾发展趋势与规律、事故危害后果,结合宁夏惠安堡原油商业储备油库这一工程实例,采用基于大涡模拟的FDS模型作为模拟计算平台,对巨型油罐火灾的燃烧过程进行数值模拟计算。通过分析计算,得到烟气分布、温度分布、热辐射强度分布等火灾过程参数的变化趋势,以及在有风和无风状态下着火罐对相邻油罐的影响,探讨现行建设工程消防技术标准就储罐防火间距、火灾时对邻近罐体冷却设计要求运用于巨型储油罐时的消防安全状况,为巨型储油罐消防安全科学合理设计提供理论依据。     

大型油罐火灾爆炸危害范围研究

针对大型油罐火灾爆炸对人员伤亡危害范围的问题，采用PHAST软件模拟定量分析了外部环境（风速、大气稳定度、空气湿度）、初始条件（泄漏点离地高度、泄漏孔直径）和其他因素（防火堤面积）对火灾爆炸伤亡半径的影响，根据模拟结果拟合了外部环境和初始条件与池火灾和蒸气云爆炸危害范围的关系式。结果表明:在相同条件下，软件模拟与实验结果误差较小，该研究具有可信性；池火灾危害范围随风速、泄漏点离地高度、泄漏孔当量直径和防火堤面积的增加而增加，而与大气稳定度的关系不大；蒸气云爆炸危害范围随风速的增加而降低，随大气稳定度和泄漏孔当量直径的增加而增加，而与泄漏点离地高度和空气湿度影响不大；拟合得到的外部环境和初始条件与池火灾和蒸气云爆炸危害范围的关系式可为大型油罐火灾爆炸事故中相关作业人员的应急撤离提供决策参考。     

The boiling liquid expanding vapour explosion

The boiling liquid expanding vapour explosion (BLEVE) has existed for a long time and for most of this time it has been cloaked in mystery. Several theories have been put forward to explain this very energetic event but none have been proven. This paper describes a series of tests that have recently been conducted to study this phenomenon.

The study involved ASME code automotive propane tanks with nominal capacities of 400 litres. The tanks were exposed to a combination of pool and/or torch fires. These fire conditions led to thermal ruptures, and in some cases these ruptures resulted in BLEVEs. The variables in the tests were the pressure-relief valve setting, the tank wall thickness, and the fire condition.

In total, 30 tests have been conducted, of which 22 resulted in thermal ruptures. Of those tanks that ruptured, 11 resulted in what we call BLEVEs. In this paper, we have defined a BLEVE as the explosive release of expanding vapour and boiling liquid following a catastrophic tank failure. Non-BLEVEs involved tanks that ruptured but which only resulted in a prolonged jet release.

The objective of this study was to investigate why certain tank ruptures lead to a BLEVE rather than a more benign jet-type release. Data are presented to show how wall temperature, wall thickness, liquid temperature and fill level contribute to the BLEVE process.     

Establishment of Aqueous Film Forming Foam extinguishing agent minimum supply intensity model based on experimental method

In recent years, serious fire and explosion accident in petrochemical storage tanks have taken place frequently. Therefore, increasing the firefighting force in petrochemical parks is particularly important. The ambition of the paper is mainly studying the supply intensity of Aqueous Film Forming Foam (AFFF) extinguishing agent. Fire extinguishing agent demand calculation method that can be capable of matching fire scale is established by carrying out series of fire extinguishing experiments. 6% AFFF is chosen to carry out three groups of experiments respectively: fire extinguishing agent fluidity determination, series groups of small size simulation oil pool fire and 177 square meters of large oil pool fire extinguishing experiment. The situation of fire extinguishing on fuel surface of AFFF can be explored through experimental means under cold and hot conditions. The data obtained from experiments prove a higher conformity between covering process and covering model under the cold condition. The model can predict the cold coverage of AFFF effectively. After unifying the supply flow from each experiment, the statistics can be fitted and come to the minimum supply intensity algorithm of AFFF against the target storage tank specifications. The algorithm is used to estimate the minimum supply intensity when extinguishing full liquid surface fire. This model also can be used as reference for petrochemical fire protection.     

On the response of 500 gal propane tanks to a 25% engulfing fire

This paper presents detailed data on the thermal response of two 500 gal ASME code propane tanks that were 25% engulfed in a hydrocarbon fire. These tests were done as part of an overall test programme to study thermal protection systems for propane-filled railway tank-cars.

The fire was generated using an array of 25 liquid propane-fuelled burners. This provided a luminous fire that engulfed 25% of the tank surface on one side. The intent of these tests was to model a severe partially engulfing fire situation.

The paper presents data on the tank wall and lading temperatures and tank internal pressure. In the first test the wind reduced the fire heating and resulted in a late failure of the tank at 46 min. This tank failed catastrophically with a powerful boiling liquid expanding vapour explosion (BLEVE). In the other test, the fire heating was very severe and steady and this tank failed very quickly in 8 min as a finite rupture with massive two-phase jet release. The reasons for these different outcomes are discussed. The different failures provide a range of realistic outcomes for the subject tank and fire condition.     

石油库储罐区池火灾事故后果模拟探讨

石油库储罐区火灾、爆炸事故危害巨大.通过对某石油库储罐区池火灾事故后果进行预测评价,对石油库储罐区池火灾事故后果模拟方法进行了讨论和对比,为石油库安全管理、安全评价和应急救援预案编制提供有益的探索.     

池火灾热辐射的数值研究

通过列举储罐火灾事故,提出对池火灾进行研究的重要性。介绍目前池火灾国内外的研究现状及发展情况,描述池火灾燃烧特征和模型。应用化学流体力学基本定律,建立了描述池火灾过程的基本控制方程组,并根据适当的条件选择辐射模型。建立物理模型,做出合理假设,确定初始和边界条件,对池火灾热辐射过程进行数值模拟,得出火焰周围入射热流密度分布图,计算出相邻两罐之间的最小安全距离,应用于工程实际中,给防火间距的制定提供理论依据,计算结果定性合理。     

On the thermal rupture of 1.9 m propane pressure vessels with defects in their thermal protection system

This paper describes the results from a series of fire tests that were carried out to measure the effect of defects in thermal protection systems on fire engulfed propane pressure vessels.

In North America thermal protection is used to protect dangerous goods rail tank-cars from accidental fire impingement. They are designed so that a tank-car will not rupture for 100 min in a defined engulfing fire, or 30 min in a defined torching fire. One common system includes a 13 mm blanket of high-temperature ceramic fibre thermal insulation covered with a 3 mm steel jacket. Recent inspections have shown that some tanks have significant defects in these thermal protection systems. This work was done to establish what levels of defect are acceptable from a safety standpoint.

The tests were conducted using 1890 l (500 US gallon) ASME code propane pressure vessels (commonly called tanks in the propane industry). The defects tested covered 8% and 15% of the tank surface. The tanks were 25% engulfed in a fire that simulated a hydrocarbon pool fire with an effective blackbody temperature of 870 °C.

The fire testing showed that even relatively small defects can result in tank rupture if the defect area is engulfed in a severe fire, and the defect area is not wetted by liquid from the inside. A wall failure prediction technique based on uniaxial high-temperature stress rupture test data has been developed and agrees well with the observed failure times.     

天然气储气罐破坏效应分析

针对城市天然气储气罐的不断兴建与发展趋势的大型化,对于已建和待建储罐区对周围环境的潜在安全性问题,指出运用破坏伤害范围评价法可直观地预测破坏效应。通过对储罐爆炸释放能量的估算,采用模拟比法结合TNT爆炸试验数据计算出距离储气罐不同距离处爆破冲击波超压值,运用超压准则模拟预测出不同规格、储压下储罐爆破破坏伤害严重程度及危及半径范围;采用世界银行推荐的危害关系式,结合伤害破坏等级分析天然气爆炸破坏效应并与爆破效应比较。5000m3储气罐、储压1.20MPa下,储罐爆破和天然气爆炸危及距离分别可达144.0m和247.7m。依据预测结果,可将罐区周围划分不同区域,为实际工程中罐区选址、建设、安全距离确定及安全预案制定提供参考。     

故障树在含硫油罐火灾分析中的应用

含硫油罐爆炸主要是由自燃、明火、雷击和静电引起的,应用故障树分析法(FTA)对其进行了分析,建立了含硫油罐爆炸的故障树.采用下行法求出了系统的最小割集,通过故障树的定性分析和定量分析,提出了预防含硫油罐火灾爆炸事故的对策,给出了具体的防爆炸措施.故障树的分析结果可以为油罐的安全管理提供理论指导.     

比较FDS和FLUENT在池火灾模拟中的应用

热辐射是池火灾燃烧的主要危害之一,可能导致人员伤亡或设备设施损坏。油罐火灾是典型的池火灾。本文通过对无风情况下油罐火灾火焰形状进行理论模型分析,建立了各自的物理模型和几何模型。应用计算流体动力学软件Fluent和火灾动力学模拟软件FDS,对无风情况下池火灾对周围大气环境的热辐射强度进行模拟,得到了火焰周围入射热流密度分布图,运用软件Statistica拟合得出热辐射强度与距离火焰中心的水平距离的对应关系,分别计算出轻伤半径区域下的最小安全距离。数值模型模拟结果与池火灾经验模型进行比较,发现FDS辐射强度结果与经验模型结果吻合较好。分析了利用这两种模型模拟油罐火灾各自的优点和缺点,最后提出了运用FDS软件模型模拟油罐火灾时的优势。     

基于热-结构耦合分析的液化石油气储罐失效预警判定*

为研究火灾中球罐应力场分布情况,找到球罐失效破裂条件,以液化石油气为研究对象,基于球罐稳态热响应,通过ANSYS热-结构耦合有限元分析法进行研究。结果表明:充装率85%的液化石油气球罐最高温度部位出现在气相区,约619.66 ℃;最大应力值出现在气液交界处,约615.18 MPa;得到球罐破裂失效时温度值和应力值,并设置2次预警值。研究结果可为液化石油气储罐失效预警提供参考和判定依据。     

凝聚态爆炸危险源外壳对爆炸冲击波影响的研究

容器中或储罐凝聚态化学危险品爆炸事故时有发生,容器或储罐壁的厚度对事故后果是否有影响,有什么影响,笔者利用非线性动力学有限元程序ANSYS/LS-DYNA,通过数值计算,研究了开阔空间带壳凝聚态爆炸危险源在空气中爆炸时,外壳厚度对爆炸应力波强度的影响。研究结果表明:易爆危险源壳体厚度的变化对爆炸冲击波的传播特性有显著影响。带壳易爆危险源爆炸作用场中的应力波峰值随距离的衰减指数与易爆危险源壳体厚度成线性关系,壳体越厚,衰减指数越大,应力波峰值随距离衰减越快。该结果为预测凝聚态易爆危险源爆炸事故后果,制定应急预案提供了科学依据。