Boiling Liquid Expanding Vapor Explosion Research Articles

Performance of double-arch tunnels under internal BLEVE

Double-arch tunnels, as one of the popular forms of tunnels, might be exposed to boiling liquid expanding vapour explosions (BLEVEs) associated with transported liquified petroleum gas (LPG), which could cause damage to the tunnel and even catastrophic collapse of the tunnel in extreme cases. However, very limited study has investigated the performance of double-arch tunnels when exposed to internal BLEVEs and in most analyses of tunnel responses to accidental explosions. The TNT-equivalence method was used to approximate the explosion load, which may lead to inaccurate tunnel response predictions. This study numerically investigates the response of typical double-arch tunnels to an internal BLEVE resulting from the instantaneous rupture of a 20 m3 LPG tank. Effects of various factors, including in-situ stresses, BLEVE locations, and lining configurations on tunnel responses are examined. The results show that the double-arch tunnels at their early-operation ages are more vulnerable to severe damage when exposed to the BLEVE due to the low action of in-situ stress of rock mass on the response of early-age tunnels. It is also found that directing the LPG tank to different driving lanes inside tunnels can affect the BLEVE-induced tunnel response more significantly than varying the configurations of tunnel lining. Moreover, installing section-steel arches in the mid-wall can effectively improve the blast resistance of the double-arch tunnels against the internal BLEVE. In addition, the prediction models based on multi-variate nonlinear regressions and machine learning methods are developed to predict the BLEVE-induced damage levels of the double-arch tunnels without and with section-steel arches.

Experimental investigation on the behavior of thermal super insulation materials for cryogenic storage tanks in fire incidents

The number of vehicles using or transporting cryogenic fuels such as Liquefied Hydrogen (LH2) or Liquefied Natural Gas (LNG) increases fast in the land transportation sector. Does this also entail new risks? The storage of cryogenic fuels requires tanks with Thermal Super Insulations (TSI) to keep the fluid cold and limit the formation of boil-off gas. TSI has proven itself in some applications since the middle of the 20th century, but in the land transport sector they are still quite new, where accidents involving fires, collisions, and their combination are to be expected. This work focuses on investigating the behavior of different types of TSI while exposed to a heat source representing a fire. To this aim, a High-Temperature Thermal Vacuum Chamber (HTTVC) was applied, which allows the thermal loading of a thermal insulation material in a vacuum and measuring the heat flow transported through the TSI in parallel. In this study, the results of 6 samples are presented regarding 3 types of MLI, rock wool, perlites, and microspheres. The thermal exposure caused different effects on the samples. In practice, this can be connected to the rapid release of flammable gases as well as to a Boiling Liquid Expanding Vapour Explosion (BLEVE). These results are relevant for reducing the risks to people and infrastructures in the progressive establishment of tanks for cryogenic fluids in our industry and society. The data presented in the study can be used to improve the design of tanks and TSIs, the assessment of accident scenarios, and the development of measures for first responders.

Prediction of BLEVE loading on structures

In a previous study by the authors, rigid structure assumption, as commonly used in analysing blast wave interaction with structures, was adapted in investigating the Boiling Liquid Expanding Vapour Explosion (BLEVE) pressure wave interaction with structures to predict BLEVE loads on structures. However, real structures are not rigid and the duration of BLEVE wave is much longer than that from high explosives and may be in the order of structural natural vibration period. Neglecting structural deformation, therefore, may lead to inaccurate predictions of BLEVE loads acting on the structure because structural deformation during the action of BLEVE wave would change the wave and the structure interaction. In this study, intensive numerical simulations are carried out using a validated computer model to investigate the influences of structural stiffness and BLEVE wave duration on the reflected BLEVE pressure on the structure. Based on the numerical results, prediction charts are proposed as a function of the BLEVE wave duration and structural fundamental vibration period for reliable predictions of BLEVE loads on structures. The findings of this study can be used to predict explosion loads in structural design against BLEVE.

Study on dynamic behavior and crack propagation mechanism of the tanks in one-step BLEVE accident

A boiling liquid expanding vapor explosion (BLEVE) is one of the most serious accidents which generates overpressure and ejected fragments with potential great impact on the safety of the tank area. Hence, it is important to reveal the dynamic characteristics of the axial crack propagation at the top of the horizontal tank in a BLEVE accident. The rupture behavior of tanks under one-step BLEVE accidents is investigated and the detailed dynamic characteristics of crack opening angle and crack propagation rate were assessed through the small-scale BLEVE experiments with variations in tank wall thickness and filling levels. An extended Gurson-Tvergaard-Needleman (GTN) model was proposed to calculate the dynamic damage of the tank during the rupture process. The dynamic stress-strain damage characteristics of the tank during the one-step BLEVE process and the circumferential transformation mechanism of the axial crack were explored. Based on an analysis of the material damage and the size characteristics of the tank structure, criteria were proposed for judging whether the direction of crack growth will change.

A damage mechanics model under dynamic thermal loads and its application to pressure vessels under fire invasion

The accurate prediction of pressure vessel rupture under fire invasion conditions is crucial for identifying boiling liquid expanding vapour explosions (BLEVEs). This study proposes a material damage model based on a calculus strategy to predict the evolution of material damage under dynamic thermal loads. In this model, the dynamic thermal load was differentiated, and the Gurson–Tvergaard-Needleman (GTN) model was combined with the Johnson-Cook (J-C) hardening function to calculate the damage within each differential time step. The stress update algorithm was used to calculate the cumulative damage. The damage characteristics of the materials at different temperatures were obtained, and the key parameters were identified as functions of temperature to describe the constitutive relationship during the dynamic damage process. The model was used to simulate and predict the failure morphology, failure time, and failure pressure of pressure vessels under fire invasion conditions. The results showed that it had good prediction accuracy and could be used to analyse BLEVE accidents involving pressure vessels.

Correlations to estimate the ground loading from small scale propane BLEVE experiments

This paper presents small-scale propane BLEVE (Boiling Liquid Expanding Vapor Explosion) experiments coupled with an investigation into ground loading dynamics. The experiments utilized cylindrical aluminum pressure vessels, with a diameter of 50 mm and a length of 300 mm. The controlled variables included burst pressure, liquid fill level, and weakened length. Both high and low-speed measurements of internal pressure and ground force were conducted during the experiments. The dependent variables analyzed were peak total ground load, force duration, and impulse. The findings from the study show trends in ground force and impulse with alterations in failure pressure, fill level and weakened length. Specifically, ground force and impulse exhibit an upward trend with increasing failure pressure, fill level and weakened length (cut length). For the first time, comprehensive correlations have been developed, incorporating the controlled variables, as well as theoretical boiling wave speed and vapor speed, to estimate the dependent variables, which represents a significant contribution in the field. However, the study does acknowledge the presence of scatter in the data, which are believed to be associated with the intricacies of the vessel opening process. It should be noted that this correlation has not been validated for larger scales. Once validated on a larger scale, these correlations can be directly applied in the design and practice of civil infrastructure to enhance the structural integrity. Additionally, the research has direct implications for industrial applications, allowing for the quantitative assessment of risks associated with bridge collapse during the transportation of PLGs.

A Model generation method and iteration algorithm for optimising fire protection thickness

With temperatures rising above 1000 °C within 5 min, hydrocarbon fire causes rapid strength degradation of structural steel members. It is among the most dangerous hazards, such as boiling liquid expanding vapour explosion (BLEVE) in the oil and gas industry. Intumescent coating as passive protection is widely adopted to prevent the steel structure from material property reduction. However, when optimising fire protection with heat transfer simulation, repetitive modelling work and lacking recalculation principle hinder productivity improvement. This method is developed to generate steel beam models and provides an effective algorithm to optimise coating thickness considering the temperature of a specific region. The main functions of the method include:•Providing section dimensions, initial insulation thickness, target temperature and heating time, temperature allowance and mesh size as variables.•Automatically generating the Abaqus steel beam model under 3-side heating conditions.•Effective iteration algorithm to modify fire protection thickness: test containing 38 Universal beam sections with a 5 °C allowance below target shows that 55.2% were completed within five iterations and 76.3% were completed within eight iterations.

Consequence Analysis of An Industrial Accident at a Fuel Station

Major industrial accident is a type of technological disaster that may require extraordinary intervention in areas outside the facility, in addition to those affected within the facility. It causes damage to the environment and loss of life at the time it occurs or afterward. Studies to be carried out to prevent these accidents Zor to reduce their effects are important. In this study, a case study for the consequences of an industrial accident that may occur in a fuel station was analyzed. Firstly, possible accident scenarios were created by obtaining chemical, atmospheric and source data. The LPG (Liquefied Petroleum Gas) storage tank (40m3) was considered in modeling a fuel station in the Korfez district of Kocaeli province, where the industry is dense in Turkey. The average atmospheric data of the province for the months of August and January were used to represent summer and winter conditions, respectively. Threat zones were produced with ALOHA (Areal Locations of Hazardous Atmospheres) software based on a release to atmosphere without burning, a jet fire as a result of a leak in the LPG tank and BLEVE scenarios. The two most dangerous scenarios were determined as a possible jet fire in August and a possible BLEVE (Boiling Liquid Expanding Vapor Explosion) in January. Overpressure effects were also obtained using the BST (Baker-Strehlow-Tang) method, thus ensuring the validation. With the software, the vapor cloud explosion distance as a result of the leak in August was obtained as 456m and 268m for the yellow (6.89kPa) and orange (24.13kPa) threat zones, respectively. Overpressure in an area of 500 meters was calculated as 5.06kPa with BST method. This calculated overpressure has the potential for damage that can lead to glass and window breakage in parallel with the ALOHA output. It has been determined that indirect injuries may occur to living beings.

Head injuries evaluation during a pipeline explosion

In recent years, Mexico has suffereda series of explosive accidents linked to oil drilling and fuel pipeline operations. These explosions are often triggered by the rapid vapor expansion due to abrupt pressure changes, known as Boiling Liquid Expanding Vapor Explosions (BLEVEs). Tragically, in 2019, a devastating explosion occurred in Tlahuelilpan, claiming the lives of at least 100 people and injuring many others. This research aims to investigate brain injuries resulting from such explosions. Despite the potential for severe injuries, there is a significant lack of comprehensive injury data, with most research focusing on military contexts. In this study, we employed the Baker method in three configurations, utilizing a finite element model, Hybrid III 50Th Percentile Male Standing, in LS-Dyna®. Head Injury Criteria (HIC) is a measure for acceleration behavior in head. Our findings indicate that this value for acceleration, and BLAST propagation radio decrease with greater analysis distance. Brain injuries include edemas, contusions, lacerations, and skull compression, predominantly affecting individuals within a 6-meter radius of the detonation point.

Consequences analysis of the LPG tank truck traffic accident: A case study of the Wenling explosion accident

Liquefied Petroleum Gas (LPG) is a vital energy source as well as a chemical feedstock, known for its flammable and explosive property. The demand for LPG has increased in recent years, leading to the frequent occurrence of leaks and explosion accidents, which pose a serious threat to public safety. This paper investigates the process of the consequences evolution of leakage of LPG and explosion accidents, using the Wenling, Zhejiang, China, LPG tanker explosion accident as an example. The main explosive processes that occurred after the leak, i.e., Boiling Liquid Expanding Vapor Explosion (BLEVE) and Vapor Cloud Explosion (VCE), were reconstructed through the collection and organization of data from the incident. The EFFECTS software was used for the simulation of container rupture, vapor dispersion and explosion pressure. The simulation results were consistent with the actual on-site effects. Multi-energy TNO method was used to measure the impact of VCE on overpressure hazards. This resulted in a blast energy of 3.1 × 105 MJ and a staff wound radius of 324 m. Based on the site's terrain and traffic route layout, measures were proposed to install protective walls around the turnaround area. Effective measures were taken to reduce the range and intensity of the explosion and thus to mitigate the consequences of the accident. This measure reduced the damage radius of the accident by 25.6%. This work will serve as a reference for investigation, analysis, scenario development and recommendations to prevent accidents.

Multi-factor coupling analysis and identification of tanks BLEVE

In a fire environment, liquid storage tanks are prone to integral cracking and eventually boiling liquid expanding vapor explosion (BLEVE), which a fireball, generates overpressure and ejected fragments with great impact on the safety of the tank area. Hence, it is important to reveal the influencing factors of the liquid storage tank failure process and the conditions that trigger integral cracking failure for the flammable liquid tank explosion accident prevention. This paper is aimed at the failure problem of metal storage tanks exposed to high temperature for a long time, through the fire experiment of small liquid tanks, taking the filling rate of tanks itself and the fire engulfment area as variables, the failure mechanism of tanks fire environment was explored from the aspects of pressure response, temperature response, failure form and tank deformation characteristics. A criterion was proposed to determine whether BLEVE will occur, which is based on the comprehensive analysis of the influence of tank internal pressure and high temperature damage of the material.

Challenges to the integrity of calandria, the CANDU PHWR moderator vessel, under serious accident loads and consequences of its failure

This paper summarizes the technical and analytical basis for a more advanced examination of structural integrity of a CANDU PHWR Calandria vessel under certain reactor accident conditions. Of foremost interest is the early Boiling Liquid Expanding Vapour Explosions (BLEVEs) induced challenge to vessel structural integrity following a spontaneous in-core rupture of a fuel channel. A sudden, flashing jet discharge of over 100 kg/s of the 10 MPa, 300 °C saturated primary coolant into its 70 °C subcooled near atmospheric pressure moderator water inventory will cause an explosive, shock wave impact. This results from rapid nucleation and vaporization of the discharged superheated liquid. Consequential pressure pulse, pipe-whip and bundle debris impact will induce damage to adjacent channels and cause widespread failure of fuel channel calandria tube rolled joints. These thin tubes inevitably deform to create serious challenges to vessel integrity. On the other extreme of reactor accidents, is the matter of an in-vessel-retention (IVR) of high temperature molten fuel debris in the reactor vessel after a severe core damage accident, such as one caused by an unmitigated station blackout. This scenario has understandably drawn greater attention after Fukushima and potential IVR in the > 200 mm thick PWR vessels when partly submerged in water is viable.It is highly unlikely that we will see reactor debris melt retention in this 19 to 29 mm thick, stepped shell with a tapestry of welds. This is because partial shell melting, diminished strength beyond 650 °C across 2/3 of the thin shell thickness and severe thermal stresses adds to underlying residual stresses near the welded seams. The result is inevitable catastrophic off-site consequences as energetic interactions upon vessel breach of water with hot debris can cause additional steam & hydrogen explosions, containment failures, and large off-site releases.This paper presents technical arguments to illustrate the problem in accepting faulty assumptions conveniently made in licensing safety assessments to simplistically claim survival of the thin-walled welded structure under these two illustrative accidents. I propose pathways to further investigations. Therefore, the issue of Calandria vessel survival under a wide range of accident conditions must be given a second, thoughtful look. Extending boundaries of a safe operating envelope as pressure tubes age needs to be avoided. We need to be more realistic in our severe accident analysis and consequence assessments. Fukushima taught us that the consequences of continuing to rely on convenient but technically faulty rationale, along with hype of eternal safety, can be very unforgiving.

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.

Prediction of BLEVE loading on a rigid structure

Boiling Liquid Expanding Vapour Explosion (BLEVE) in open space has been investigated in the authors’ previous study. However, for designing structures against BLEVE event, BLEVE load acting on structures, instead of the pressure in open space, should be used in the structural response analysis. Therefore, further study is required to accurately predict BLEVE loads on structures. In this study, 1300 sets of BLEVE cases consisting of 650 wave propagation in open space and 650 pressure wave-structure interaction cases are numerically modelled. The open space BLEVE pressure and reflected pressure waves from the rigid structure are simulated, and the corresponding impulses are calculated. The reflection coefficient chart is developed to predict the reflected BLEVE overpressure on the rigid structure. The diffraction and clearing effects on the reflected waves are analysed with respect to the dimensions of the structure. An empirical formula for predicting the reflected impulse is also proposed. The results obtained in this study can be used together with the open space BLEVE pressure predictions presented by the authors in a previous study to predict the BLEVE loads on structures.

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 RfM). 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 RfM 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).

Accident consequence assessment of benzene leakage from storage tank in a chemical park in Bengbu City, China

AbstractBenzene is widely used in chemical industries and has a high potential to cause damage. The release of benzene from storage tanks can generate threats to workers, facilities, and the environment. The effects and consequences of benzene release from a storage tank during the dry and rainy seasons were investigated with the Areal Locations of Hazardous Atmospheres (ALOHA) software program. Risk distributions were obtained through threat zones classified by red, orange, and yellow colors. The results showed that the maximum hazard areas related to benzene vapor cloud and flammability in rainy seasons were greater than those in the dry seasons. There was no significant difference in the consequences of the thermal radiation from pool fire and the Boiling Liquid Expanding Vapor Explosion (BLEVE) scenario in both the rainy and dry seasons. The maximum threat zones were determined to be 2200 and 305 m for the toxic benzene vapor cloud and the flammable area, respectively. The consequences of the pool fire and BLEVE scenario of benzene were at a distance of 101 and 3600 m from the storage tank, respectively. This study is expected to play an important role for decision‐makers in preventing benzene‐related accident risks and to reducing loss.

Prediction of BLEVE loads on structures using machine learning and CFD

Boiling Liquid Expanding Vapour Explosions (BLEVEs) are driven by complex fluid dynamics with expanded vapour and flashed liquid. They may generate strong shock waves that lead to catastrophic consequences to personnel and structures in the vicinity. Despite the great interest in safety management and intensive research efforts, reliable and efficient prediction of BLEVE loads on structures is still challenging in practice. Computational Fluid Dynamics (CFD), based on complex physics formulas, can provide more accurate predictions of BLEVE loads than the traditional empirical and TNT-equivalency approaches, but suffers from high computational costs. Data-driven machine learning models offer efficient surrogates but conventional models, including commonly used multi-layer perceptron (MLP), are suboptimal especially for explosions of complex geometry and in complex environment. In this study, a novel machine learning approach, based on the state-of-the-art Transformer neural networks, is developed for BLEVE loads prediction on an idealised structure in the vicinity of BLEVE. Through extensive experiments and rigorous evaluation, it is shown that Transformer can effectively model the structure-wave interaction, yielding accurate pressure and impulse predictions with less than 14% relative errors, which outperforms widely used MLP (20% error) significantly. The developed Transformer model is applied to predict critical parameters of BLEVE loads, including arrive time, rise time and duration. The results demonstrate that Transformer can produce an accurate pressure-time history, yielding a comprehensive characterisation of BLEVE loads on structures.

Modeling the risk of acetone emission from a storage tank in summer and winter

AbstractThe leakage of acetone from damaged tanks can threaten workers, surrounding facilities, and the environment. The safe storage of acetone is of vital importance for emergency planning and response. This paper focused on the effects and consequences of acetone leaks from a 200 m3 storage tank in the summer and winter seasons by the employment of Areal Locations of Hazardous Atmospheres. The hazard zones classified as red threat zone, orange threat zone, and yellow threat zone were determined and analyzed. Results showed that the risk distribution of the toxic acetone vapor cloud in summer was greater than those in winter. The summer and winter seasons have no significant effect on the thermal radiation intensities from pool fire and the Boiling Liquid Expanding Vapor Explosion (BLEVE) scenario. The maximum distance of toxicity, flammability, and thermal radiation from the pool fire and BLEVE scenario for the acetone leakage were 547, 111, 16, and 1100 m, respectively. The results would provide guidance for decision‐makers in safety management and emergency response to reduce hazards.

LPG stored at the wildland–urban interface: recent events and the effects of jet fires and BLEVE

Background Jet fires and boiling liquid expanding vapour explosions (BLEVEs) are potential events when a vessel containing liquefied petroleum gas (LPG) is exposed to fire. Events involving domestic LPG tanks have occurred at wildland–urban interface areas in Portugal, the USA, Spain and Greece. Aims Evaluation of the pressure relief device (PRD), the type of cylinder and the effects of jet fires and BLEVEs. Methods LPG cylinders manufactured with steel and composite materials were exposed to fire. Hydrostatic tests were carried out to compare the burst pressure without fire influence. Fourteen accidents that occurred during wildfires are described. Key results The presence of a PRD and the right choice of type of cylinder as well as cylinder location may avert major accidents. The jet fires and fireball radiation are also described, as well as the maximum distance reached by cylinder fragments. Conclusions The tests showed that the burst pressure in the test of a cylinder without PRD under fire was significantly lower when compared with the hydrostatic tests. Implications Lastly, recommendations to avoid accidents are made.

Rethinking “BLEVE explosion” after liquid hydrogen storage tank rupture in a fire

The underlying physical mechanisms leading to the generation of blast waves after liquid hydrogen (LH2) storage tank rupture in a fire are not yet fully understood. This makes it difficult to develop predictive models and validate them against a very limited number of experiments. This study aims at the development of a CFD model able to predict maximum pressure in the blast wave after the LH2 storage tank rupture in a fire. The performed critical review of previous works and the thorough numerical analysis of BMW experiments (LH2 storage pressure in the range 2.0–11.3 bar abs) allowed us to conclude that the maximum pressure in the blast wave is generated by gaseous phase starting shock enhanced by combustion reaction of hydrogen at the contact surface with heated by the shock air. The boiling liquid expanding vapour explosion (BLEVE) pressure peak follows the gaseous phase blast and is smaller in amplitude. The CFD model validated recently against high-pressure hydrogen storage tank rupture in fire experiments is essentially updated in this study to account for cryogenic conditions of LH2 storage. The simulation results provided insight into the blast wave and combustion dynamics, demonstrating that combustion at the contact surface contributes significantly to the generated blast wave, increasing the overpressure at 3 m from the tank up to 5 times. The developed CFD model can be used as a contemporary tool for hydrogen safety engineering, e.g. for assessment of hazard distances from LH2 storage.