Explosion Accidents Research Articles

The Storage Tank Explosion Damage and the Effectiveness of Control Measures in the Chemical Industrial Parks of Smart Cities

Safety is one of the goals of a smart city. To study storage tank explosion damage in a city’s chemical industrial parks, determine the position of control measures according to the situation, and realize the analysis of the measured utility, we proposed the area damage probability importance distribution. In this way, the prediction and prevention of risk in chemical industrial parks can be achieved intelligently. The concept of area damage probability importance distribution was given, and the utility analysis method of the control measures for storage tank explosion accidents was put forward. It is concluded that the area damage probability importance distribution represents the change degree of damage probability: that is, the damage degree of storage tank explosion in a chemical industrial park. The control measures for a storage tank explosion can be set up in varying positions, as the explosion damage is mainly caused by shock waves; the blast walls are selected as the measure set, and the calculation method for the area damage probability is modified. By comparing the calculated area damage probability distribution before and after, evaluation of the control measures’ effectiveness can be achieved. Finally, the flow chart of the algorithm is given. The example analysis shows that the calculation process and analysis results meet the design requirements of the algorithm. The effectiveness of the method, the distribution characteristics, and the significance and function of the importance distribution of damage probability are discussed. This provides an effective method for smart cities to predict and prevent the impact of an explosion at chemical industrial parks.

Experimental investigation on the development characteristics of high-pressure hydrogen jet flame under different ignition conditions

With the rapid development and application of hydrogen in the chemical and energy industry, the safety of hydrogen industrial facilities has been widely concerned. In this study, the safety of hydrogen accidently released from a high-pressure tube storage system (tube diameter:10 mm, storage tank volume:4 L) was explored experimentally. The combustion behavior of the transient hydrogen jet and explosion overpressure under self-ignition and electric spark induction were investigated. Besides, the explosion overpressure and jet flame evolution laws of the hydrogen cloud induced by the release of unsteady turbulent hydrogen jets into the open environment were analyzed. The results revealed that the peak value of hydrogen self-ignition explosion overpressure was higher than that of electric spark ignition overpressure. Compared with spark ignition, hydrogen self-ignition flame structures can be maintained for longer time. However, spark ignition at low release pressures was more likely to cause hydrogen ignition and explosion compared to self-ignition. Finally, the combustion behavior and potential hazards of the ignited free transient hydrogen jet under different ignition modes were analyzed. This study can provide a reference for the prevention and control of hydrogen explosion accidents in practice.

Light-induced, room-temperature hydrogen gas detection based on SnO2 quantum Dots/p-Si

The continuous monitoring of the hydrogen gas level under low-temperature conditions is vital to prevent explosive accidents. Metal oxide-based chemoresistors have attracted significant attention owing to their excellent gas sensitivity. However, high operating temperature required to remove adsorbed oxygen species is still considered as an obstacle, limiting the application of the system. In addressing the temperature issue, this study introduced an approach in which a gas interaction layer was separated from the signal-sensing region. The proposed two-terminal device comprises a gas interaction layer of SnO2 quantum dots (QDs) and a p-doped silicon (p-Si) region characterized by high electronic conductivity and light sensitivity. Through visible light illumination, the recombination between gas interaction-induced electrons and photo-generated holes induces a change in output photocurrent, enabling room-temperature gas sensing without additional temperature control. Using this gas sensing scheme, the proposed sensor showed impressive gas detection performance in the low-temperature range, achieving a detection range of a few parts per million (ppm) in concentration (limit of detection range: 9.46–50 ppm).

Experimental and numerical simulation of the attenuation effect of blast shock waves in tunnels at different altitudes

Traffic engineering such as tunnels in various altitudinal gradient zone are at risk of accidental explosion, which can damage personnel and equipment. Accurate prediction of the distribution pattern of explosive loads and shock wave propagation process in semi-enclosed structures at various altitude environment is key research focus in the fields of explosion shock and fluid dynamics. The effect of altitude on the propagation of shock waves in tunnels was investigated by conducting explosion test and numerical simulation. Based on the experimental and numerical simulation results, a prediction model for the attenuation of the peak overpressure of tunnel shock waves at different altitudes was established. The results showed that the peak overpressure decreased at the same measurement points in the tunnel entrance under the high altitude condition. In contrast, an increase in altitude accelerated the propagation speed of the shock wave in the tunnel. The average error between the peak shock wave overpressure obtained using the overpressure prediction formula and the measured test data was less than 15%, the average error between the propagation velocity of shock waves predicted values and the test data is less than 10%. The method can effectively predict the overpressure attenuation of blast wave in tunnel at various altitudes.

Analysis of Spill Accident Damage Scale and Explosion Accident Impact Distance of Hazardous Material Transportation Vehicles

Analysis of Spill Accident Damage Scale and Explosion Accident Impact Distance of Hazardous Material Transportation Vehicles

Numerical derivation of pressure-impulse (P-I) diagrams of prefabricated RC columns with steel joints subjected to blast loads

In recent decades, terrorist attacks and accidental explosions have occurred frequently. The casualties are not only caused by the shock wave, but also by the structural collapse initialed from the failure of structural columns. In this paper, the dynamic response and damage mechanism of prefabricated reinforced concrete (RC) columns with steel joints (PRC) subjected to blast loads are numerically investigated. By comparing the numerical results with the experimental results, the accuracy of the finite element (FE) model is firstly verified. Then, dynamic responses and damage of PRC under blast loads induced by the TNT explosions and vapor cloud explosions (VCEs) are investigated and compared with each other. The results indicated that PRC damage under VCEs with 9.3 MPa is larger than that under TNT explosions. Conversely, the damage under VCEs with 7 MPa is smaller than that under TNT explosions, and the blast-induced damage and dynamic behavior of PRC under two types of explosions is different. Subsequently, parametric studies are further carried out to investigate the influence of key parameters of PRC, including longitudinal and transverse reinforcement ratio, column dimensions, concrete strength, steel sleeve dimensions on PRC damage. It is revealed that different parameters affect the damage for PRC column in different load regions of P-I diagrams, including the impulsive load region, dynamic load region and quasi-static load region. Increasing the sleeve length, sleeve ratio and transverse reinforcement ratio improves the shear-resistant performance of PRC, and these parameters more easily affected PRC damage in the impulsive load region. Increasing the concrete strength and column depth can increase the blast-resistant performance of PRC in three load regions. Based on parametric studies, pressure-impulse (P-I) diagrams for damage evaluation of PRC under VCEs and TNT explosions are proposed and verified. Finally, Blast-resistant design procedure of PRC based on P-I diagram is developed.

A quantitative internal-short-circuit diagnosis method of lithium-ion batteries for float charging systems

The diagnosis of internal short circuit (ISC) faults in lithium-ion batteries (LIBs) plays an important role in improving battery safety and reducing the occurrence of fire and explosion accidents. Traditional ISC diagnosis methods mainly focus on dynamic operating conditions, and rarely consider stable float charging scenarios with high risks. This paper proposes a quantitative diagnosis strategy for ISC faults in LIBs under different float charging conditions. First, a simulation model of ISC faults for single cells and battery modules under float charging conditions is established. Then, for the LIB packs without a balancing system, three quantitative diagnosis methods (namely Map-based, constant-voltage-source based, and intermittent-charging based) for the ISC faults applicable to different simple and complex float charging systems are proposed. Finally, the method is verified through simulation and experiments, and the results show that an ISC of 0–500 Ω can be detected in various scenarios, and the proposed methods are low-cost, high-precision, and easy to implement for early ISC diagnosis of float charging systems for energy storage.

Research on the consequences of hydrogen leakage and explosion accidents of fuel cell vehicles in underground parking garages

Explosion risks in confined spaces hinder the widespread use of hydrogen fuel cell vehicles. This study investigates the consequences of hydrogen leakage and explosion accidents from fuel cell vehicles parked in underground garages. Results indicated that downward leaks generate a larger flammable gas cloud size, peak value of VQ8, and areas of danger 3, 1.2, and 2 more times than upward leaks. Meanwhile, upward leaks result in more extensive damage to steel structures and glass. Flammable gas cloud continuous accumulation occurs between beams owing to parking near a wall, whereas the flammable gas cloud maximum extent decreases by half upon parking adjacent to side walls. However, the radius of burns and minor injuries does not vary with parking position. Compared to a single-vehicle situation, multiple surrounding vehicles considerably expand the range of flammable gas clouds and burn hazard area with increases of 57.9% and 53%, respectively.

Numerical study on the influence of venting interlayer structure on the explosion venting effects

Catering is an important business format of commercial complexes in Chinese Mainland, and most of its kitchens use natural gas as fuel. However, once natural gas leaks, it is very easy to cause explosion accidents. For kitchens without external windows in large commercial complexes, the horizontally arranged explosion venting interlayers should be installed to lead the explosion vents from the kitchens to the exterior walls of the buildings. The paper conducts modeling research on linear and 90° bend, as well as interlayers containing structural beams (obstacles), and obtains the explosion propagation laws of different explosion venting interlayer structures. After the flame enters the venting interlayer, the presence of obstacles can cause flame acceleration; the peak pressure in the kitchen shows an increasing-sudden decreasing-increasing trend as the distance between obstacles and the explosion outlet decreases. When the obstacle is located 2.5 m away from the interlayer inlet, the maximum flame propagation speed can reach 356.5 m/s. The effects of the bend structure on the propagation process of gas explosion venting have been investigated. The peak overpressure of 90° bend venting interlayer is 1.52 times that of the linear interlayer. However, there is a notable reduction in peak overpressure (approximately 26.6%) observed post-bend. Additionally, an increase in the distance preceding the bend results in an initial rise followed by a decline in peak overpressure, while the shock wave attenuation coefficient displays a trend of first increasing and then decreasing.

A risk decision support model for hydrogen refueling stations based on cloud-analytic hierarchy process

With the rapid development of the hydrogen energy industry and the vigorous promotion of the application of hydrogen fuel cell vehicles, hydrogen refueling station (HRS) has gradually penetrated into cities, mostly built in densely populated areas. Once leakage, fire, and/or explosion accident occurs, it is highly likely to cause casualties, property damage, and environmental pollution. In order to avoid HRS risks, this paper establishes a risk decision support model based on Cloud-Analytic Hierarchy Process for HRS. Firstly, the static and dynamic features of HRS emergency plan selection are analyzed, and the weight coefficient of each feature is determined by using the cloud analysis hierarchy process. Then, the case-based reasoning theory and the weighted Euclidean distance based on the cloud model are used to establish a decision support model based on emergency plan optimization. Finally, taking the HRS hydrogen storage tank fire as an example, the risk decision support model based on the cloud analysis hierarchical process is applied to form the optimal scheme of the HRS hydrogen storage tank fire emergency plan. The results show that the weighted Euclidean distance scheme selection method based on cloud model can be effectively combined with the weight acquisition method based on cloud analysis hierarchy process to provide decision support for HRS emergency risk management and control.

Simulation on the Dispersion of Natural Gas and its Volume Cloud Distribution on an Offshore Fixed Platform

The formation, migration and volume distribution of gas clouds, which are dominated by natural gas after oil and gas leakage, are the material basis of fire and explosion accidents on offshore platforms. Based on an offshore platform as the background, this paper conducts research on the gas cloud using numerical simulation method, the selection of different wind speeds, leak leakage rate of quality, wind direction and the direction angle, the leakage of gas diffusion behaviour simulation studies and its size distribution. There is a “coupling” effect on the volume value of 5% CH4 cloud between different wind speeds, leakage mass rates, and wind direction and leakage direction. When the wind speed is 13 m/s, the leakage mass velocity is 8 kg/s, and the included angle between wind direction and leakage direction is 180°, the “coupling” effect on the volume value of 5% CH4 cloud increases significantly. The above research results can provide a reference for the reasonable division of process risk area, firewall design and quantitative risk assessment of fire and explosion of an offshore platform.

A generic approach for modelling hydrogen-methane-air detonation in hydrocode

Hydrogen is pivotal in the transition to a sustainable energy supply. The presence of hydrogen-methane mixtures is increasing as the feasibility of utilizing existing natural gas infrastructure for large-scale hydrogen transportation and distribution. However, recent explosion accidents underscore the need to understand the detonation hazards of hydrogen and methane. Current modelling techniques for hydrogen-methane-air detonations are computationally prohibitive due to extra-fine mesh and time step requirements to solve the chemical reaction coupling within detonation structure. This study presented a generic approach to address these challenges, enabling precise and rapid simulation of hydrogen-methane-air blast profiles within hydrocodes. Modified open-source codes helped bypass the time-consuming implicit coupling of detailed chemical reactions with detonation structure and thermodynamic properties based on Chapman-Jouguet (C-J) theory and equilibrium reactive flow assumption, yielding a 90% reduction in computational time. An empirical model, developed through theoretic calculations, provided C-J parameters for hydrocode input with high accuracy across typical industrial conditions. Then, these C-J parameters were employed in LS-DYNA hydrocode based on modified Jones-Wilkins-Lee (JWL) equation of state (EoS) to simulate the hydrogen-methane-air blast loading. This approach was validated against diverse experimental data, encompassing hydrogen-air, methane-air, and hydrogen-methane-air mixtures, and various fuel concentrations, experimental scales, confinement conditions, and fuel shapes. Although conservative results were observed in unstable detonations near the lower detonable limit, it outperformed traditional CFD methods in both accuracy and efficiency. Furthermore, the use of hydrocodes enables the analysis of blast loading as well as the dynamic behaviour of structures subjected to explosive forces. This approach is easily adaptable to other gaseous detonations beyond hydrogen-methane-air by simply replacing the chemical reaction models, making it a versatile tool across various fields.

Effect of sulfur-containing groups on the susceptibility to spontaneous combustion of corrosion products in oil tanks

Sulfur-containing groups (SCG) may be an essential factor influencing the spontaneous combustion of oil tank corrosion products and triggering fire and explosion accidents. The effect of three SCG on the spontaneous combustion susceptibility of model compounds of tank corrosion products (MCTCP) were investigated. The results show that SCG causes the surface of MCTCP to produce cracks and become rough, which adsorbs more oxygen and SCG, enhancing its spontaneous combustion susceptibility. After the SCG addition, the MCTCP thermal susceptibility partial indicator values decreased. The apparent activation energy and the flammable volatile compound release temperature decreased significantly, which increased the spontaneous combustion susceptibility of MCTCP. In addition, SCG also increased the number of exothermic peaks in the self-ignition process of MCTCP. The exothermic peaks partly came from the oxidation of SCG, and the heat generated by the oxidation of SCG increased the spontaneous combustion susceptibility. Therefore, SCG may affect the spontaneous combustion susceptibility through three pathways: changing the microform and structure of MCTCP, thermal susceptibility parameters, and oxidative exothermic properties. The work assists in deepening the theory of the mechanism and influence factors of spontaneous combustion of corrosion products in oil tanks, and provide guidance for the prevention of such accidents.

Experimental Evaluation on Blast Resistance of Reinforced Concrete Structures under Partially Confined Explosion

As the risk of accidental explosions at ammunition storage or hydrogen charging station increases in populated area, it is needed to design the facilities against blast loading, particularly subjected to partially confined explosion. However, the partially confined explosion lacks experimental test data to efficiently design the facilities subjected to the potential threat, when compared to unconfined or confined explosion cases. As a fundamental study on partially confined explosion, two partially buried tunnel-type structures with normal- and high-strength concretes were tested under a weight charge of 5.9 kg TNT explosion. The major parameters were concrete compressive strength and reinforcement ratio. The test result showed that the damage of the concrete structure with normal-strength concrete was extremely severe, whereas that of the specimen with high-strength was relatively mild. Further, finite element (FE) analyses were performed to investigate the confinement effect of blast load. The FE analysis result showed that under partially confined explosion, the reduction of the maximum displacement by using higher concrete strength was significant, while preventing the failure of the structure. This study provides fundamental data for designing the facilities with explosives subjected to the partially confined explosion.

Thermal Hazard Analysis of Two Non-Ideal Explosives Based on Ammonium Perchlorate/Ammonium Nitrate and Aluminium Powder.

In recent years, various kinds of civil explosive detonation accidents have occurred frequently around the world, resulting in substantial human casualties and significant property losses. It is generally believed that thermal stimulation plays a critical role in triggering the detonation of explosives; consequently, the study of the thermal hazards of explosives is of great significance to many aspects of safety emergency management practices in the production, transportation, storage, and use of explosives. It is known that the thermal stability of the ammonium perchlorate-aluminium system and the ammonium nitrate-aluminium system has been extensively investigated previously in the literature. However, there is a paucity of research on the thermal hazard characteristics of non-ideal explosives under varying oxygen balance conditions within the academic sphere. Therefore, this research focused on the study of the thermal hazards of non-ideal explosives based on thermokinetic analysis. The thermal hazards of non-ideal explosive mixtures of ammonium perchlorate and aluminium and of ammonium nitrate and aluminium were studied by thermal analysis kinetics. The thermokinetic parameters were meticulously studied through differential scanning calorimetry (DSC) analysis. The results showed that the peak reaction temperature and activation energy of the ammonium perchlorate-aluminium system were significantly higher than those of the ammonium nitrate-aluminium system. Under the condition of zero oxygen balance, the peak reaction temperature of the ammonium nitrate-aluminium system was 259 °C (heating rate 5 °C/min), and the activation energy was 84.7 kJ/mol. Under the same conditions, the peak reaction temperature and activation energy of the ammonium perchlorate-aluminium system were 292 °C (heating rate 5 °C/min) and 94.9 kJ/mol, respectively. These results indicate that the ammonium perchlorate-aluminium system has higher safety under the same thermal stimulation conditions. Furthermore, research on both non-ideal explosive systems reveals that the activation energy is at its peak under negative oxygen balance conditions, recorded at 104.2 kJ/mol (ammonium perchlorate-aluminium) and 86.2 kJ/mol (ammonium nitrate-aluminium), which indicates a higher degree of safety. Therefore, the investigation into the thermal hazards of non-ideal explosive systems under different oxygen balance conditions is of utmost importance for the enhancement and improvement of safety emergency management practices.

The response characteristics and damage effects of large LNG storage tanks subject to the coupled effects of explosion shock waves and fire

As the demand and import of liquefied natural gas (LNG) increase, large LNG receiving stations are being constructed. LNG leakage can lead to fire or explosion accidents. The simultaneous occurrence of explosions and fires, often inevitable, is more damaging than the effect of a single load. This study utilizes finite element analysis software LS-DYNA and the ALE algorithm to examine the response characteristics and damage effects on large LNG storage tanks under the combined impact of explosion shock waves and high-temperature loads (with the explosion preceding the fire). The findings indicate that post-explosion, the concrete outer tank's compressive strength diminishes as temperatures rise. The dome deflection of the storage tank's external tank surpasses the standard limit at 400 °C and fails at 600 °C. This research identifies the critical failure mode of the concrete storage tank's outer tank under the joint impact of explosion shock waves and fire. It provides a foundation for the anti-explosion design of such storage tanks.

Streptococcus mitis and Klebsiella pneumoniae Mixed Infection in Severe Burn Injury Patient

Burns are a significant problem with high associated morbidity and mortality worldwide. Bacteremia is a serious complication that is important in increasing the overall fatality rate in burn injury patients. In this study, we report a case of Streptococcus mitis and Klebsiella pneumoniae mixed infection in severe burns in a 40-year-old female. The patient was transferred from an outside hospital to the emergency unit after burn injuries in a gas explosion accident at home. The patient underwent surgical debridement and antibiotics treatment but died due to sepsis and multiorgan failure. Our case study will help to underscore the important role of Streptococcus mitis and Klebsiella pneumoniae as human opportunistic pathogens in severe burn injury patients.

Numerical Analysis of Harmful Environmental Impact of Accidental Explosion at a Hydrogen Filling Station Environmental Impact of an Accident Hydrogen Explosion at a Gas Station

The purpose of this study is to evaluate numerically the consequences of a hydrogen-air mixture explosion at a vehicle hydrogen filling station. The physical process of the explosion, which takes place after the hydrogen gas release into the air due to the accidental destruction of a number of high-pressure storage cylinders, is considered. The blast pressure wave moves in all directions from the epicenter of the accident, gradually losing its intensity and having a negative shock impact on the service personnel of the filling station and the structures of the surrounding buildings. The scale of the accident depends on the number of destroyed cylinders, which determines the size of the hydrogen-air cloud and the power of the explosion. The degree of negative consequences for the environment depends on the maximum overpressure in the blast wave front. Numerical obtaining of spatial pressure distributions in the area of the accident based on a hydrogen explosion mathematical modeling makes it possible to separate zones that are dangerous to human health and building structures strength. The direct problem of gas dynamics of combustion products of a hemispherical cloud of a stoichiometric hydrogen-air mixture in the surface layer of the atmosphere is considered. The mathematical model of an instantaneous hydrogen explosion takes into account the three-dimensional and non-stationary nature of the propagation of the explosion wave, the compressibility of the gas flow, the complex terrain, the shape and initial concentration of the cloud of hydrogen combustion products, and their thermodynamic parameters. The model makes it possible to obtain three-dimensional fields of maximum overpressure, which are the basis for deterministic assessment of the consequences of an accident for human health and the integrity of structures in the area of the explosion. The presented computer technology allows security experts to identify potential dangerous zones by means of mathematical modeling, recommend effective protective measures to mitigate or even eliminate the negative consequences of the blast wave environmental impact.

Temperature response and chemical reactions of energetic materials under thermal radiation and heat conduction

Thermal radiation from a high-temperature source is the primary cause of energetic material explosions. However, current research cannot meet the need to prevent thermal radiation-caused explosions. This paper proposes a novel numerical calculation model for temperature response and the chemical reaction of energetic materials under thermal radiation based on the physical mechanisms and evolution of the thermal effect during the chain explosion accident. This model is essential for rapidly evaluating the effect of thermal radiation in chain explosion accidents. The numerical model in this study efficiently obtained the thermal response of energetic materials under thermal radiation, as well as the critical conditions for energetic material explosion under thermal radiation. The results reveal that heat conduction is difficult to cause the explosion of ammonium nitrate, but thermal radiation can. The critical temperature of explosion for ammonium nitrate is 1668 K, the critical duration is 15.93 s, and the critical distance is 7.85 m. The temperature, duration, and radiation distance of the heat source are crucial factors that induce the ammonium nitrate explosion. Firefighters must cover and protect ammonium nitrate within 7200 s and 15.93 s, respectively, when the external heat flow absorbed by the material is 2.688 kW/m2 and 28 kW/m2. The model proposed in this paper can predict the effect of thermal radiation once the heat source parameters are known. Besides, combined with machine learning, the model can also predict the heat source parameters once the parameters of the thermal radiation effect are known. Compared with the current numerical models to evaluate the effect of thermal radiation, the numerical model presented in this paper can evaluate the effect of thermal radiation in engineering more efficiently and has broad application prospects.

The impact of spatial layout on safety risks of urban natural gas pipelines

This paper primarily investigates the influence of spatial layout on the safety risks associated with urban natural gas pipelines. Drawing from the actual spatial configuration around the pipeline and local climatic characteristics, the study delves into the distribution patterns of natural gas leakage diffusion and explosion accident consequences, considering various factors such as leakage apertures, soil porosity, and spatial layouts. By integrating the outcomes of the consequence analysis, the quantitative risk of urban natural gas pipelines, accounting for the impact of spatial layout, was computed and juxtaposed with the results of traditional two-dimensional risk analysis. The findings underscore that spatial layout exerts a substantial impact on risk distribution, with significantly elevated risk values in more congested spatial layouts. Additionally, the introduction of a barrier along the pipeline leakage path resulted in a 91.4% reduction in risk compared to scenarios without obstruction. It is evident that the spatial layout surrounding the pipeline plays a pivotal role in influencing the distribution of pipeline failure risks, establishing the spatial environment as a critical factor in risk analysis. This study offers valuable insights for urban land planning, safety control line establishment, and related considerations.