立式锅炉爆炸机理试验研究

通过对立式锅炉爆炸事故案例汇总分析,得知立式锅炉占爆炸锅炉的60%~70%,且爆炸主要原因是缺水和超压。基于锅炉缺水导致材料力学性能改变及再进水超压造成内胆失稳,进行了材料高温力学性能试验、缺水再进水试验和内胆失稳模拟试验。得知严重缺水会造成炉胆过热超温,材料抗拉强度、弹性模量和刚度大幅下降,且350~500℃区域材料性能下降明显;立式锅炉缺水再进水爆炸事故主要是由进水汽化造成锅内压力骤升引起,缺水和超压同时存在,炉胆外压作用下失稳;立式锅炉在下脚圈与筒体连接的对接焊缝,炉胆、筒体和炉门圈的角焊缝处最易造成焊缝撕裂。     

矿井瓦斯爆炸传播的尺寸效应研究

基于瓦斯爆炸传播过程的理论分析 ,确定了表征瓦斯爆炸传播过程的主要物理参数 ;通过在两条巷道中进行了瓦斯爆炸传播的对比实验 ,指出了瓦斯爆炸传播过程的尺寸效应存在的原因。笔者认为 :因为巷道支护设备使巷道有效面积的减少和壁面粗糙度的变化 ,尺寸效应使大断面巷道在可比条件下 ,发生瓦斯爆炸时 ,爆炸波的火焰、压力、冲量等在更大范围内形成破坏和伤害     

障碍物对瓦斯爆炸冲击波影响研究

为研究障碍物对瓦斯爆炸冲击波传播规律的影响,利用水平管道式气体——粉尘爆炸实验装置,测试并分析障碍物数量、尺寸和壁面粗糙程度对瓦斯爆炸冲击波超压、冲击波传播规律的影响。结果表明:障碍物对瓦斯爆炸过程中冲击波传播规律具有重要影响。障碍物存在时,改变了爆炸冲击波的传播规律,提高了冲击波超压的最大峰值压力,且随着障碍物数量和尺寸的增加,这种激励作用越明显。随着壁面粗糙程度的增大,瓦斯爆炸冲击波超压明显增大。研究结果对井下巷道瓦斯爆炸冲击波的防治具有一定的指导意义。     

中小锅炉爆炸事故规律分析与研究

为研究中小型锅炉爆炸事故的规律,对中小型锅炉爆炸案例进行调查和分析,并进行了缺水再进水试验和炉胆失稳模拟试验。研究认为,爆炸主要原因是缺水和超压,缺水造成材料性能下降明显,进水汽化造成锅内压力骤升,并给出了立式锅炉爆炸机理。从锅炉结构、水容积、安全附件等方面的爆炸事故因素考虑,对3种中小型锅炉进行安全性分析,并提出了事故预防措施。     

汽车爆炸的超压分布规律实验研究

测试了不同药量和不同车型的爆炸超压值,对汽车爆炸的超压分布规律进行了实验研究.结果表明,小汽车内发生炸药爆炸时,车门侧压力明显大于车尾部方向的压力,车外的冲击波超压值要大于空气中炸药爆炸的结果,前者约为后者的1.0～2.2倍.即车体对冲击波约束作用要小于车内底盘的反射作用.计算得到了实验中冲击波超压对人员的杀伤半径和最小安全距离,对汽车爆炸案件具有一定指导作用.冲击波的反射不可忽视,货车下地面炸药爆炸表现出明显的冲击波反射作用,测得超压值大于空气中爆炸的超压值.     

一烘筒超压爆炸

2004年9月底的某天晚上，常州市某村办助剂厂发生一起烘筒超压爆炸事故。爆炸造成3间厂房坍塌。操作工人因逃离及时未受伤害。爆炸前，厂房内安置着2台直径1m的烘筒，烘筒无出厂铭牌及资料，简体及平板封头为碳钢，投用后一直未经过有关部门的检验。     

煤矿巷道瓦斯爆炸传播规律及破坏效应分析

井下瓦斯爆炸的影响因素众多,随机性强,分析和研究瓦斯爆炸的传播规律只有通过巷道模拟实验的方法。通过对爆炸过程中爆炸压力、温度、速度等相关参数随时间、空间的变化规律的分析,进一步研究瓦斯爆炸的机理和破坏效应,在煤矿生产过程中采取合适的阻隔防爆技术措施,减少瓦斯爆炸带来的损失。     

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。     

Prediction of BLEVE mechanical energy by implementation of artificial neural network

In the event of a BLEVE, the overpressure wave can cause important effects over a certain area. Several thermodynamic assumptions have been proposed as the basis for developing methodologies to predict both the mechanical energy associated to such a wave and the peak overpressure. According to a recent comparative analysis, methods based on real gas behavior and adiabatic irreversible expansion assumptions can give a good estimation of this energy. In this communication, the Artificial Neural Network (ANN) approach has been implemented to predict the BLEVE mechanical energy for the case of propane and butane. Temperature and vessel filling degree at failure have been considered as input parameters (plus vessel volume), and the BLEVE blast energy has been estimated as output data by the ANN model. A Bayesian Regularization algorithm was chosen as the three-layer backpropagation training algorithm. Based on the neurons optimization process, the number of neurons at the hidden layer was five in the case of propane and four in the case of butane. The transfer function applied in this layer was a sigmoid, because it had an easy and straightforward differentiation for using in the backpropagation algorithm. For the output layer, the number of neurons had to be one in both cases, and the transfer function was purelin (linear). The model performance has been compared with experimental values, proving that the mechanical energy of a BLEVE explosion can be adequately predicted with the Artificial Neural Network approach.     

BLEVE: The case of water and a historical survey

After a short update of the current more accepted definition of BLEVE, the special features of water BLEVEs are analyzed. The stronger overpressure wave generated in the case of water as compared to that of other substances is justified in terms of volume change. Through a comparison with liquefied pressurized propane, three possibilities are analyzed: the simultaneous contribution of both the liquid and the preexisting vapor, the contribution of the liquid flash vaporization, and the contribution of the pre-existing vapor. Also a historical survey on a set of 202 BLEVE accidents –the largest sample of BLEVE accidents surveyed until now– is presented. LPG was the most common substances in this set of accidents. However, water and LNG (11% of water and 4% of LNG in the studied cases) have also been involved. Impact failure (44.8%) and human factor (30.3%) were the most common causes of BLEVEs. Transport, storage, process plants, and transfer were the activities in which more accidents occurred.     

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。     

BLEVE火球热辐射及其影响评价模型介绍

高压液化易燃、易爆化学品储罐易发生BLEVE,引起热辐射,会造成周围人员伤亡和设备损坏.介绍了BLEVE火球热辐射及其影响模型,通过该模型可以计算BLEVE火球的尺寸、持续时间、升空高度、热辐射通量及预测暴露在BLEVE火球热辐射通量下人的致死概率.     

扑救液化石油气储罐爆炸火灾安全距离的确定

液化石油气储罐爆炸火灾是一类比较难于扑救的特殊火灾，如何根据现场的情况快速评估事故危害，并确定灭火指挥和人员疏散的安全距离，是消防指挥员指挥决策的重要问题，也是难点问题。本文研究了液化石油气储罐发生BLEVE时的热辐射和冲击波计算方法，并导出了安全距离的确定方法。对于消防指挥员快速决策具有十分重要的意义。     

BLEVE: Safety distances estimation by simple models based on the Jakob number

One of the most important points in the design of inherently safe processes is to estimate reliable distances among process units at preliminary stages of the plant project to minimize losses and damages caused by the potential occurrence of technological accidents. Therefore, in this paper the achievement of simple, general, dimensionless and reliable equations (Simple Dimensionless Models SDMs) for the direct estimation of safety distances considering the occurrence of BLEVE (Boiling Liquid Expanding Vapour Explosion) event, is proposed. The developed models directly relate safety distances with critical design/operation variables (involved substance, vessel volume, target vulnerability and explosion temperature), which are easily accessible at early stages of the plant project. SDMs are achieved by analysing the influence of these simple variables on the safety distances, which are estimated using a selected rigorous model (Reference Model R_fM). This task is simplified by the incorporation of the Jakob Number as an input variable, allowing to obtain dimensionless models and simultaneously an adequate representation of the explosion conditions and the involved substances. As result, the achieved SDMs demonstrate a particularly good fit with respect to the R_fM estimations and, at the same time, reliability and versatility. As it is shown in the analysed study cases (involving critical decision variables for the process design and the system safety), the SDMs prove to be also accurate, general, and easily incorporable into more complex optimization problems (QRA analysis, design of emergency plans, safety distance estimation to minimize the probability of domino effects, optimal layout designs, among others).     

Assessing the hazards from a BLEVE and minimizing its impacts using the inherent safety concept

Many worlds' major process industry accidents are due to BLEVE such as at Feyzin, France, 1966 and San Juan Ixhuatepec, Mexico City, 1984. One of the approaches to eliminate or minimize such accidents is by the implementation of inherently safer design concept. This concept is best implemented where the consequence of BLEVE can be evaluated at the preliminary design stage, and necessary design improvements can be done as early as possible. Thus, the accident could be avoided or minimized to as low as reasonably practicable (ALARP) without resorting to a costly protective system. However, the inherent safety concept is not easy to implement at the preliminary design stage due to lack of systematic technique for practical application. To overcome these hurdles, this paper presents a new approach to assess process plant for the potential BLEVE at the preliminary design stage and to allow modifications using inherent safety principles in order to avoid or minimize major accidents. A model known as Inherent Fire Consequence Estimation Tool (IFCET) is developed in MS Excel spreadsheet to evaluate BLEVE impacts based on overpressure, radiation heat flux and missile effects. In this study, BLEVE impacts are the criteria used as the decision-making for the acceptability of the design. IFCET is integrated with iCON process design simulator for ease of data transfer and quick assessment of potential BLEVE during the design simulation stage. A case study was conducted to assess of potential BLEVE from a propane storage vessel at the design simulation stage using this new approach. The finding shows promising results that this approach has a potential to be developed as a practical tool.     

On the mechanism of a BLEVE occurrence due to fire engulfment of tanks with overheated liquids

The BLEVE (boiling liquid expanding vapor explosion) effect that involves the formation of a fireball occurs at the engulfment by fire of a tank with a highly flammable liquid or a liquid gas. Heating of the tank causes elevation of the liquid phase temperature and pressure inside the tank. A partial rupture of the dry tank walls is possible, with the formation of a rarefaction wave propagating into the liquid phase. An evaporation wave moves after the rarefaction wave and cause a rapid increase of pressure, exceeding the initial pressure before depressurization. Rapid violent destruction of the tank occurs. The mechanism of a BLEVE initiation is considered using Van der Waals isotherms. The following criterion for the possibility of a BLEVE was formulated. If the final state is located on an unstable part of the Van der Waals isotherm, a BLEVE takes place. Limiting values of the temperatures for overheating of certain highly flammable liquids and liquid gases (propane, n-butane, n-pentane, isopentane) were calculated using the proposed method, and were found to be in good agreement with experimental data available in the literature.     

Hazard analysis on LPG fireball of road tanker BLEVE based on CFD simulation

In order to research the hydrocarbon fireball characteristic of LPG tanker Boiled Liquid Evaporate Vapor Explosion (BLEVE) under different conditions, computational fluid dynamics (CFD) simulations of the hydrocarbon fireballs from the LPG tanker BLEVE accidents were carried out. Several new different factors, such as the mass of fuel, inlet velocity and airflow velocity, were considered to analyze the influence on the evolution of the characteristics of the fireball and the development of the LPG tanker BLEVE accidents. Results indicate that the fireball with a greater mass of fuel radiates more heat but slower. The large longitudinal diameter of the fireball and high radiation heat flux are observed in case of a faster inlet velocity used for the same mass. The airflow was found to shorten the initial phase of the fireball effectively. Some suggestions were proposed to prevent the LPG BLEVE accidents. Analysis performed show that various parameters like fireball diameter, radiative heat flux and lifting speed of fireball can be predicted well using FDS code.     

The Boiling Liquid Expanding Vapour Explosion (BLEVE): A bibliometric review and futur trends

The phenomenon “Boiling Liquid Expanding Vapor Explosion” (BLEVE) is one of the most common accidental events in the chemical industry and in the transport of dangerous goods. A bibliographic search in the Web of Science Core Collection reported 375 publications related to BLEVEs from 1979 to the present (August 10, 2022). A bibliometric analysis was conducted using the VOSviewer tool to allow a better understanding of the scientific knowledge on this phenomenon. A comprehensive overview of BLEVE research is presented in terms of annual publication, top journals, countries/regions with the highest productivity, authors and their cooperation networks, key terms, and co-citation analysis. The 375 publications cover 691 authors, 83 journals, 44 countries or territories and 290 institutions. The key publication (highest number of citations and co-citations) for understanding the BLEVE phenomenon is. The results obtained constitute a snapshot of the current state of the art on BLEVEs and can be applied to improve the understanding of research on this topic and establish new trends of research.