Fire and explosion hazard analysis during surface transport of liquefied petroleum gas (LPG): A case study of LPG truck tanker accident in Kannur,Kerala, India

This paper presents an analysis and simulation of an accident involving a liquefied petroleum gas (LPG) truck tanker in Kannur, Kerala, India. During the accident, a truck tanker hit a divider and overturned. A crack in the bottom pipe caused leakage of LPG for about 20 min forming a large vapor cloud, which got ignited, creating a fireball and a boiling liquid expanding vapor explosion (BLEVE) situation in the LPG tank with subsequent fire and explosion. Many fatalities and injuries were reported along with burning of trees, houses, shops, vehicles, etc. In the present study, ALOHA (Area Locations of Hazardous Atmospheres) and PHAST (Process Hazard Analysis Software Tool) software have been used to model and simulate the accident scenario. Modeling and simulation results of the fireball, jet flame radiation and explosion overpressure agree well with the actual loss reported from the site. The effects of the fireball scenario were more significant in comparison to that of the jet fire scenario.     

Pressure and temperature increase of LPG in a thermally coated pressure vessel exposed to fire: Experimental and model results

Damage caused by incidents with transport tanks with compressed liquified gas is amongst the most extreme that can be encountered with transport vessels. This is particularly the case with the Boiling Liquid Expanding Vapor Explosion (BLEVE), which may occur if such a tank is exposed to fire for a prolonged period. Therefore, the local Dutch LPG transport sector adopted a thermally insulating tank coating as a ‘standard outfit’ for their tank trailers, with the aim to delay a BLEVE for a sufficiently long period for emergency services to take appropriate measures and for people near the accident location to be evacuated. On a European scale however, no consensus has been reached on the cost-benefit of such measures.With the current drive towards “greener” and renewable energy sources, this issue has regained attention with alternative fuels such as LNG, CNG and Hydrogen and a need was felt for (better) theoretical models and experimental data concerning the behavior of transport tanks carrying these substances.In this paper a new tank thermal (equilibrium) model is described to predict pressure and temperature behavior of a multi layered, thermally insulated tank containing a compressed liquified gas exposed to heat. Results are compared with data of three bonfire experiments, in which 3 m³ tanks, filled for ca. 50% with LPG were exposed to fire. A good match between modelled and experimental pressure and temperature evolution in time could be obtained using a constant value for the thermal conductivity of the insulation layer. The modelling showed that the thermal insulation value is crucial for an accurate prediction of these parameters as well as the opening time for a pressure safety valve. As relevant temperatures may cover a very wide range (from cryogenic in LNG-tanks to over 1000 °C in a fire) knowledge of the thermal (and physical) behavior of the insulating layer over a large temperature range is essential.The same holds for the behavior of the PRV when subjected to fire. Extreme temperatures may also lead to deviating behavior from what is expected based on the initial settings.     

事故树分析法在LPG储罐火灾爆炸事故中的应用

LPG(液化石油气)属于危险化学品之一,LPG储罐发生火灾爆炸的机率大,造成的损失比较严重,故对其火灾爆炸事故进行研究具有重要意义。LPG储罐爆炸根据其发生机理分为化学爆炸(燃爆)和物理爆炸两种模式。本文通过对LPG储罐燃爆﹑物理爆炸两类事故进行系统分析,建立了以LPG储罐燃爆、物理爆炸为顶事件的事故树。通过对其事故树的定性分析,得到了影响顶事件的各个最小割(径)集。通过计算底事件的结构重要度,确定了影响LPG储罐火灾爆炸事故的主要因素,并提出了相应的改进措施,进而提高LPG储罐的安全性和运行可靠性。     

LPG球罐BLEVE过程中超压与热耦合效应模拟研究

为评估LPG球罐发生BLEVE过程中超压与热耦合效应对化工企业抗爆控制室和避难所选址的影响,采用TNO多能法数学模型计算冲击波超压,采用多源数学模型计算火球热辐射。编写MATLAB计算程序,并应用ANSYS模拟二者破坏效应的耦合作用。LPG球罐发生BLEVE过程中,爆炸冲击波的传播速度、持续时间和火球的传播速度、持续时间不同,爆炸冲击波主要在燃料高速抛散的初期形成,之后基本与火球脱离。分别模拟计算冲击波超压和火球热辐射对抗爆控制室和避难所的影响,结果表明：抗爆控制室选址只需考虑爆炸冲击波的影响;避难所选址需要考虑冲击波超压和火球热辐射作用双重影响。在研究基础上提出,LPG球罐附近人员逃生的避难所应设置在球罐防火堤外紧邻防火堤处的地下,应具有抗震、防渗、防火、防中毒窒息等功能。人员应在BLEVE发生前进入避难所才能逃生。     

Analysis of the boiling liquid expanding vapor explosion (BLEVE) of a liquefied natural gas road tanker: The Zarzalico accident

The road accident of a tanker transporting liquefied natural gas (LNG) originated a fire and, finally, the BLEVE of the tank. This accident has been analyzed, both from the point of view of the emergency management and the explosion and fireball effects. The accidental sequence is described: fire, LNG release, further safety valves release, flames impingement on vessel unprotected wall, vessel failure mode, explosion and fireball. According to the effects and consequences observed, the thermal radiation and overpressure are estimated; a mathematical model is applied to calculate the probable mass contained in the vessel at the moment of the explosion. The peak overpressure predicted from two models is compared with the values inferred from the accident observed data. The emergency management is commented.     

LPG罐区火灾爆炸事故危险性分析

针对重大危险源LPC罐区的火灾爆炸事故频发,首先采用数学泄漏模型分析油罐泄漏,然后应用池火、火球、喷射火火灾和UVCE及BLEVE爆炸事故的数学伤害模型分别分析几种重要的火灾和爆炸事故后果,并针对定量的事故后果分析对安全距离作出预测.     

液化石油气球罐泄漏危险的预防和控制探讨

阐述了液化石油气球罐的特点。对液化石油气球罐的泄漏危险性进行了分析,主要存在的泄漏危险有泄漏物质易燃易爆、易发生泄漏、受热易膨胀导致泄漏、泄漏气体易积聚、泄漏事故具有隐蔽性、泄漏物质具有毒害性。根据液化气泄漏危险性分析,提出了预防和控制液化石油气球罐泄漏危害的安全措施:加强设备质量管理,杜绝泄漏现象;合理设置球罐,降低泄漏风险;规范安全操作,减少泄漏量;防止泄漏气体积聚;设置防泄漏安全装置;及时发现泄漏;设置消防给水及灭火设施;妥善处理泄漏事故。     

LPG罐区事故后果模拟与风险控制研究

LPG在储存过程中,可能由于泄漏或灾难性破裂等原因引发火灾、爆炸、中毒等重大事故。首先根据两类危险源理论,辨识与分析了LPG罐区的危险源及其危险性。然后,利用事件树方法,建立了瞬时泄漏和连续泄漏后果模型。通过研究典型的事故后果计算与模拟分析方法、风险确定与表示方法,借助PHAST和LEAK系统模拟分析与计算了某LPG罐区发生泄漏后的事故后果及其影响,并绘制了个人风险等值线和社会风险F-N曲线。最后,根据分析结果提出了多项针对性的风险控制措施。     

LPG船液货泄漏事故风险评估系统研究

通过对液化石油气(LPG)船舶液货舱泄漏事故危险度因素分析,建立液化气液体货物泄漏源强、蒸气释放源强和蒸气扩散计算模型,并制定泄漏事故风险评价流程,基于VB语言编写泄漏事故风险评估系统。利用该系统能够计算得出泄漏事故发生后蒸发气在不同时刻不同区域的蒸发气浓度、爆炸或火灾后对生命财产的伤害半径以及伤害程度等相关参数。对某航行状态下的LPG实船进行模拟分析,结果表明能够对LPG船舶泄漏事故进行有效风险评估,并能对船舶航行安全应急预案的制定和事故后海事鉴定提供一定的技术帮助。     

液化石油气站储罐区火灾爆炸危险性分析与安全措施

选择具体的液化石油气储配站,分析了该站的危险特性、危险产生的途径及可能造成的后果。在没有任何防护措施的情况下,采用蒸气云爆炸和沸腾液体扩展蒸气云爆炸模型,对该站一个50m3储罐发生泄漏造成的火灾爆炸事故后果进行预测,得出火灾爆炸后的安全距离为大于211．0m。在储配站不能满足此安全距离的基础之上,从防止产生爆炸性气体环境、消除点火源和抑制事故扩大三方面来提出有效的安全措施,降低事故发生的概率及事故造成的损失。其中,站址选在全年最小频率风向的上风侧且周围空旷的地区,罐上设置液位计、压力表、温度计及可燃气体报警器可防止产生爆炸性气体环境;罐及管道设静电接地,法兰用铜线跨接,站内设警示标志可消除点火源;生产区与辅助区间设置隔离墙,罐区周围设置砖混围堤,罐上设安全阀可抑制火灾爆炸事故扩大。     

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。     

瓦斯爆炸中的火球伤害效应

针对瓦斯爆炸事故3种危害中的高温热辐射伤害进行研究,结合火灾爆炸事故中的火球热辐射的传播公式,得出适合井下瓦斯爆炸事故的火球传播规律公式.依据该公式划分了瓦斯爆炸事故中火球热辐射的死亡、重伤、轻伤的半径公式,为瓦斯爆炸事故安全评价提供了理论基础.     

过程液氯贮槽装置封闭厂房及事故氯吸收塔联用安全效用分析

分析、设立液氯贮槽液相泄漏的几种典型事故情景,并利用液相泄漏、液池蒸发、重气扩散和人员中毒死亡概率等模型对比研究封闭厂房及事故氯吸收塔等安全措施对液氯贮槽液相泄漏扩散中毒后果的影响,给出不同事故情景下液氯泄漏速率、液池半径、液池蒸发速率、室外氯气中毒死亡概率等事故后果特征值。对封闭厂房及事故氯吸收塔安全效用进行定量分析和比较研究。结果表明,液氯贮槽的封闭厂房对抑制液氯泄漏扩散中毒事故后果效用明显;事故氯吸收塔能消除液氯贮槽微小孔泄漏所对应的小事故情景,还能对封闭厂房最严重泄漏事故后果起到初期削峰作用。显然,封闭厂房及事故氯吸收塔联用可以降低液氯贮槽事故影响后果,具有良好安全效用。     

大型LPG罐区火灾爆炸事故后果评估

针对大型LPG(液化石油气)储罐区潜在的火灾爆炸危险性，建立了喷射火、火球、UVCE爆炸和BLEVE爆炸的数学伤害模型，对其发生火灾、爆炸后人员和建筑(设备)所受到的伤害和损伤进行了定量后果评估。     

Assessment of the Consequences of Accident Scenarios Involving Dangerous Substances

This paper highlights major steps in the procedure for evaluating the consequences of accidents involving dangerous substances, especially during the storage, and loading/unloading activities. The procedure relies on identifying accident scenarios that could be encountered at particular plants, followed by a modelling of these scenarios by means of available modelling systems. Finally, the resultant outcomes are identified, together with their effects on both people and property. The resources needed to perform this procedure are discussed, in order to clarify the roles of plant operators, external experts and other institutions when evaluating any accident consequences. Four examples, all relevant in industrial practice, are given in order to illustrate the procedure: the releasing of liquified petroleum gas, flammable organic solvents, toxic chlorine, and oil fuels. The results of these studies may be used for a quick order-of-magnitude estimation of accidents consequences.     

CFD-based assessment and visualization of the failure consequences of LPG tankers

This paper presents a simulation analysis of the explosions following an LPG leak and visualizes the consequences of the accident to reduce the consequences of the LPG leak explosion. Firstly, this paper proposes a CFD numerical simulation-based method for visualizing the consequences of LPG tanker failure. The method combines satellite maps and CFD numerical simulation data to visualize the consequences of LPG leaks and explosions, taking into account the influence of obstacles on the danger range of leaks and explosions; Secondly, this paper applies the method to a liquefied petroleum gas accident that occurred in the Wenling section of the Shenhai Expressway and performs CFD numerical simulation on the accident process and visualizes the consequences of the accident. Therefore, this method can provide a theoretical reference for the prior prevention of LPG accidents and the analysis of the consequences of accidents, as well as certain practical guidance instructive.     

铁路与油库安全距离不足的技术解决方案

针对南水北调国家重点工程中的国家铁路线(临时)和油库LPG储罐、卸气栈桥及卸油栈桥安全距离不足问题,通过典型事故后果模拟,分别模拟了LPG储罐底部管线全管径破裂泄漏、LPG栈桥液相管全管径破裂泄漏及成品油栈桥管线全管径破裂泄漏等3种事故情景可能事故后果效应及影响范围,研究了各类事故后果与临时铁路线、临时围墙间相互关系及影响,提出了有针对性的安全对策措施.     

液化石油气BLEVE事故研究

为了减小液化石油气沸腾液体扩展蒸汽云爆炸事故后果,采用ALOHA软件对液化石油气储罐泄漏事故进行研究,基于液化石油气泄漏量、空气湿度、风速、储存温度等爆炸事故后果影响因素进行数值模拟。研究结果表明:液化石油气泄漏量越大,沸腾液体扩展蒸汽云爆炸事故产生的火球直径越大,燃烧时间或热辐射时间越长,且造成的危害范围越大,事故后果越严重;随着空气湿度增加,事故影响的范围逐渐减小,事故后果相对减小;随着液化石油气储存温度增加,事故影响范围逐渐减小;风速对于事故影响范围无影响;空气湿度、储存温度及风速对火球直径及火球燃烧时间无影响。     

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.     

Fire and explosion disasters occurred due to the Great East Japan Earthquake (March 11, 2011)

The Great East Japan Earthquake (magnitude 9.0 Mw: the moment magnitude scale, based on the seismic moment of the earthquake) occurred at 14:46, March 11, 2011. It triggered huge tsunami waves (seismic sea waves) that reached heights of up to about 20 m. In this paper, the fire and explosion disasters occurred due to the Great East Japan Earthquake are reported shortly. Some fires occurred in seacoast areas after tsunami attacks and some of them were spreading very widely to the tsunami flooded areas. It is important to study the mechanisms of such fires (tsunami fires) for preparing huge tsunami. After the earthquake, a very severe accident happened in the Fukushima Daiichi nuclear power plant. Three reactors experienced full meltdown. During this disaster, hydrogen explosions occurred and made the situation more serious. It has to be realized once again that the countermeasures for hydrogen explosions is indispensable. Also Large scale BLEVEs (Boiling Liquid Expanding Vapor Explosions) happened at LPG storage area in an oil refinery in Chiba Prefecture. This accident started from the falling down of an LPG storage tank by earthquake motions. The tank was heavier than usual, as it was filled with water (1.7 times heavier than LPG) for periodic inspection. Considering these disasters, we have to think about how we prepare the accident of low probability and of very severe consequence. Recently, the risk based approach is widely utilized. However, for such disasters it seems not enough to perform safety management only by risk based approach. Not only probabilistic approach (Risk), but also deterministic approach (Emergency plan, Mitigation technique) should be taken in account.