Search Results (108)

In chemical industrial parks, evacuation during LPG tank leakage is governed not only by travel distance but by the loss of safe corridors, failed exits, and congestion induced by spatially coupled vapor exposure, explosion overpressure, and thermal radiation. Existing consequence assessment studies usually delineate hazardous zones, while evacuation models often optimize routes on a fixed network with available exits and simplified capacity constraints; the coupling between multi-hazard consequence fields and capacity-constrained evacuation assignment remains insufficient. This study proposes a spatially constrained, congestion-aware evacuation optimization framework. ALOHA-derived AEGL exposure, vapor cloud explosion overpressure, and jet fire radiation zones are mapped onto the plant network to identify unsafe nodes, unavailable links, and failed exits. A capacity-constrained model is then established to minimize system-level RSET under an ASET constraint, and a congestion-aware ant colony algorithm balances evacuees among available exits by incorporating risk and density penalties. In a petrochemical plant case with 717 evacuees and 74 nodes, Gate 3 failure makes the nearest-exit strategy infeasible, whereas the proposed strategy reduces RSET from 560.8 to 504.9 s. The framework links accident consequence assessment with actionable evacuation routing for chemical parks. Full article

Accurate simulation modeling of the danger zone and real-time visualization of the toxic cloud spread during a fire and explosion at an industrial facility in a nearby urban area are in demand by rescue services conducting evacuation. Using a cellular automaton method allows us to create an optimal predictive model of the danger zone spread, combine modeling accuracy with computational speed, and consider multiple input variables and the cascading nature of an accident during visualization. The objective of this study was to develop a mobile application for calculating the parameters of the danger zone during an accident at an industrial facility caused by a toxic cloud spreading into an urban area, based on the selection of a cellular automaton algorithm. The primary objective of the study was a highly detailed visualization of the danger zone with several predicted values of toxic substance concentrations in the air. The authors developed a cellular automaton-based model, which forms the basis of the mobile application. It takes into account several variables characterizing chemicals in the explosion and fire zone, climate factors, occupancy, building parameters, and the availability of respiratory protection. The FireSoft Mobile app was developed using the Visual Studio 2022 development environment, C# 10.0, and .NET MAUI, adapted for Android 8.0 and higher. The mobile app was tested to visualize a cloud of toxic pollutants forming a hazardous zone in an urban agglomeration for cases involving an ammonia tank explosion and a large fire involving a large amount of polyvinyl chloride. The results demonstrate the app’s feasibility and effectiveness in predicting, planning, and managing evacuation measures during accidents at an industrial facility. Full article

As sustainable development becomes increasingly important, technologies for liquid hydrogen (LH₂) storage and transportation are advancing rapidly. Safety concerns regarding LH₂ tanks in fire accidents require further attention. In this study, a one-dimensional thermodynamic model was developed based on layer-by-layer analysis to assess the heat transfer performance of the insulation structure in LH₂ tanks under fire conditions. Through the transformation of the solving target and iteration rules, a novel and efficient solution method was proposed for such thermodynamic problems. The thermodynamic performance of the insulation structure coupled with spray-on foam and variable-density multilayer under normal temperature (NT) and standardized fire conditions (863.15 K) was analyzed, and the effects of insulation structure parameters and environmental factors were evaluated. A case study of a 500 L vehicle LH₂ tank was conducted using the software package BoilFAST, with the total heat leakage as the key input, to analyze the evolution of internal pressure and temperature. Results show that within the insulation structure, temperature decreases rapidly by 80.35% and 89.55% under fire and NT conditions, respectively. Spray-on foam insulation thickness, layer density, residual gas pressure, and hydrogen temperature exert minor effects, while the temperature of the external environment and the number of layers significantly affect the heat flux under the fire condition. Under the NT condition, heat leakage is primarily attributed to support structures and accessory pipelines, whereas under the fire condition, heat leakage from the insulation structure becomes the main source, accounting for 63%. This study provides a reference for heat transfer assessment of LH₂ tanks in fire scenarios. Full article

In a tank farm, even if the separation distance meets the codes and standards, a pool fire in one tank may spread quickly to another tank. Most destructive and uncontrollable fire accidents are induced with multiple pool fires. In current work, the thermal buckling behaviors of a fixed-roof tank subjected to one (two) neighboring pool fire(s) (burning tanks) are numerically studied. The effects of the number of the pool fires, the separation distance between two pool fires, and the distance between the adjacent tank and pool fires are analyzed. The results indicate that the thermal buckling zone of the target tank subjected to two pool fires is larger than that subjected to one pool fire, and the maximum displacement for two pool fires is almost equal to that for one pool fire. The target tank subjected to one pool fire loses stability and reaches a new stable state faster than that subjected to two pool fires. The thermal buckling zone expands as the distance between the two pool fires increases but decreases with increasing separation distance between the pool fire and the target tank. The findings provide useful guidance for the structural optimization of steel storage tanks against pool fire exposure and offer theoretical support for emergency response and fire rescue in tank farms. Full article

To improve the flexibility of coal-fired power units and support renewable energy integration, molten salt thermal storage has been widely considered a promising retrofit option. However, under unified operating conditions, the comparative effects of different heat-release pathways and steam extraction ratios on flexibility, full-cycle thermodynamic performance, and economic performance have not been sufficiently clarified. In this study, a thermodynamic model of a 600 MW subcritical coal-fired power unit coupled with a two-tank molten salt thermal storage system was established in Ebsilon and validated against the design heat-balance data under typical load conditions, with maximum relative deviations of 0.06% for power output, 0.95% for main steam flow rate, and 1.24% for heat consumption rate. Three representative heat-release pathways were comparatively investigated under identical heat-storage conditions, with steam extraction ratios ranging from 2% to 18%. The results show that increasing the extraction ratio raises the thermal storage capacity from 9.762 to 84.636 MWh and enhances the downward peak-shaving capability, but weakens the full-cycle thermodynamic performance. Among the three schemes, Scheme 2 exhibits the strongest upward peak-shaving performance, with upward peak-shaving energy increasing from 2.893 to 24.395 MWh, and also yields the highest annual net profit (0.546–4.342 million CNY). Scheme 3 exhibits the best full-cycle thermal and exergy efficiencies, with full-cycle thermal efficiency of 42.76–41.56% and full-cycle exergy efficiency of 38.34–37.27%. In addition, Schemes 1 and 2 show significantly higher round-trip efficiencies than Scheme 3, with Scheme 2 becoming more advantageous at higher extraction ratios. Scheme 1 exhibits the shortest static payback period (7.12–7.63 years) and the highest internal rate of return (12.77–11.65%). These results indicate that the three schemes have distinct advantages in peak-shaving performance, full-cycle thermodynamic performance, and economic performance, and provide a comparative basis for engineering selection and parameter optimization of molten-salt-based flexibility retrofits in coal-fired power units. Full article

The widespread adoption of hydrogen fuel cell electric vehicles (FCEVs) is currently hindered by the significant cost and lack of geometric flexibility of conventional Type IV pressure vessels made from carbon fiber reinforced plastic (CFRP). These tanks are difficult to integrate into future vehicle platforms optimized for modular batteries. This study, therefore, presents a novel compressed hydrogen storage system (CHSS) based on a modular assembly of seamless steel cylinders. The objective of this approach is to create a design-flexible and cost-effective alternative that adapts to the limited installation space of modern electric vehicle architectures while offering a sustainability advantage through the high recyclability of steel. The system was specifically designed to meet the stringent requirements of the UNECE R134 regulation and subsequently subjected to rigorous experimental validation. The evaluation included all four test sequences required for component certification: Baseline Tests, Performance Durability Test, On-Road Performance Test and Fire Test. The successful validation demonstrates that the developed modular steel-based CHSS meets all relevant safety and performance requirements. It, therefore, represents a technically and economically promising technology that can make a decisive contribution to accelerating hydrogen mobility through its superior design flexibility and sustainability. Full article

Obstacles can significantly affect the thermal radiation distribution of oil storage tank fires; however, this issue has received relatively limited attention in previous studies. Taking aviation kerosene fires as an example, this study employed a cylindrical flame radiation model combined with the Monte Carlo method to investigate the variation in the radiative flux incident on the target and the flame-target view factor under different obstacle widths (W), heights (H) and target distances (d). The results indicate that obstacles block the flame radiation path, thereby reducing the radiative flux in the region behind the obstacle compared with the unobstructed condition. The view factor first decreases with increasing W and then approaches a stable value. The critical width (W_cr) is independent of H but increases with d. A similar relationship is observed between H and the critical height (H_cr). Based on geometric analysis, analytical expressions for W_cr and H_cr were derived. In addition, a predictive model for the view factor shielding ratio (φ) was established using three dimensionless geometric parameters, achieving a coefficient of determination of R² = 0.976, which demonstrates good predictive accuracy. These findings provide theoretical guidance for fire risk assessment in tank farm areas. Full article

The convergence of sensing and processing is a critical frontier in the development of energy-efficient spiking edge intelligence. This paper presents a novel hardware implementation of a sensory neuron evolving from the leaky integrate-and-fire (LIF) model by coupling a volatile memristor with an LC tank circuit. The proposed memristor–resistor–inductor–capacitor (MRLC) neuron embeds electromagnetic sensing directly into neuronal dynamics, enabling direct transduction of proximity information into spike trains. We demonstrate that the circuit functions as a metal-sensitive proximity sensor with spiking output in both simulation and physical experiments. Moreover, the MRLC neuron exhibits rich dynamical regimes, including regular spiking, bursting with 2–5 spikes per burst, and quasi-chaotic behavior, as well as sensing memory provided by hysteresis-like multistability, which is a notable advancement over simple rate-encoding LIF neurons. Full article

Ensuring the driving safety of hazardous chemical vehicles is a critical priority. High temperatures in tires and tanks can lead to catastrophic accidents, including fires and road damage, particularly in bridge and tunnel sections. Therefore, the purpose of this study is to utilize deep learning to obtain the temperature of vehicle tires and tanks in real time. We constructed a comprehensive dataset by combining the FLIR infrared vehicle dataset, the SPT visible tire dataset, and self-collected thermal video frames captured in various environments. State-of-the-art object detection models, including different scales of YOLOv8, YOLOv9, and YOLOv10, were evaluated for the multi-target detection of vehicles, tires, and tanks. Comparative analysis reveals that the YOLOv8-L model optimized with the GIoU loss function delivers the best performance. Specifically, it achieves a mean Average Precision (mAP) of 97.9% with an average inference time of 6.9 ms per frame, effectively balancing accuracy and real-time efficiency. Finally, by mapping the detection bounding boxes to the radiometric temperature matrix, the system achieves precise, real-time temperature monitoring of the vehicle components. Full article

Modeling and visualizing zones within the spread of toxic clouds from fires and explosions during accidents at industrial facilities located near residential areas is of high practical value. This tool is critical for the rapid planning of population evacuation measures and emergency response. Of particular importance is the development of computer software that can quickly model the hazard zone of toxic cloud spread and superimpose it on a terrain map to determine the potential impact on residential areas. This software should be based on a mathematical model that can accurately predict the parameters of the hazard zone both near the industrial facility and beyond it, at a distance of more than 1 km. The objective of this study is to create algorithms for modeling the hazard zone during a fire or explosion at an industrial facility using a cellular automaton method and to develop a software tool for its visualization. The software must display the hazard zone for the population of a nearby residential area on a map in real time, which is necessary for assessing potential harm to residents’ health and in planning their rapid evacuation. To achieve this objective, this article presents a model for determining the boundaries and main parameters of a hazard zone based on the cellular automaton method (frontal and probabilistic). The proposed model takes into account both constants (properties of chemical substances, building parameters, population size, etc.) and variables (the mass of the substance at each explosion and fire, wind speed and direction, air temperature, etc.). The FireSoft III software, developed by the authors and based on the cellular automaton model, provides more rapid calculation of the parameters and delineation of the hazard zone boundaries compared to similar software, which was tested in cases of an ammonia tank explosion and a prolonged fire in a warehouse containing polyvinyl chloride at an enterprise. This makes FireSoft III promising for use in a fire and explosion response at enterprises. Full article

In response to the complexity and uncertainty in assessing the safety and economic impacts of the Changed Product Rule (CPR) in civil aviation products’ airworthiness certification, this paper constructs a comprehensive evaluation model based on a cost–benefit analysis framework. In previous research, studies on aircraft modification costs have consistently been conducted from the perspective of design organizations, focusing on modeling and optimizing the one-time engineering costs of the modifications themselves or remaining confined to the level of safety performance without addressing the calculation of economic value. The model proposed in this paper considers the entire aircraft service lifecycle and uniformly quantifies potential impacts into monetary terms for comparison. The model encompasses safety improvements, cost estimation, and discounted cash flow analysis, aiming to provide decision-makers with quantitative tools for determining the applicability of the “impracticality exception” standard. This ensures that modifications to aviation products balance safety with economic viability. Through case studies involving fuel tank access panel design changes and Auxiliary Power Unit (APU) inlet duct fire protection requirements, the effectiveness and practicality of the model are validated, offering an empirical foundation for future policy formulation and industry regulation. Nevertheless, the parameters in the model depend on historical data, and appropriate parameters must be carefully selected. Although the model has taken into account the entire lifecycle of the aircraft, it is still based on static assumptions and fails to consider the impact of the rapid development of the aviation industry over time. Ongoing model refinement, international data collection, and integration of non-economic factors remain key directions for future research. Full article

Anaerobic digestion of sugarcane vinasse is integral to enhancing ethanol distilleries’ environmental and energy performance by converting organic waste into biogas; however, the flammable and toxic nature of biogas has led to significant safety concerns, particularly in anaerobic bioreactors where biogas is produced and stored. This study provides a comparative risk assessment of different anaerobic reactor configurations—a covered lagoon biodigester (CLB), a continuous stirred-tank reactor (CSTR), an upflow anaerobic sludge blanket reactor (UASB), and an anaerobic structured-bed reactor (AnSTBR)—processing vinasse, focusing on fire, explosion, and hydrogen sulfide (H₂S) toxicity hazards. Jet fire scenarios posed the most severe threat, with fatal outcomes extending up to 66 m, while the fireball scenario exhibited no lethal range. The risks to human life from explosions were minimal (1.2%). H₂S toxicity was identified as the most critical consequence, with particularly severe impacts in CLB systems, where the hazardous zone was up to 20 times larger than in AnSTBR. Therefore, the design of anaerobic bioreactors for vinasse treatment must primarily address the risks associated with H₂S-rich biogas, as reactor configuration plays a key role in mitigating or amplifying these hazards—high-rate systems such as AnSTBR and UASB demonstrating safer profiles due to their compact design and lower gas storage volumes. Full article

With the rapid expansion of electric vehicles, the risk of battery fires has become a critical safety concern. Conventional suppression methods, such as submerging battery packs in large water tanks, are inefficient due to long response times and potential secondary hazards. This study introduces a polymer-based fire suppression tube system that automatically activates under specific conditions. The system utilizes energy from a C4 explosion to rupture the tube, rapidly releasing the extinguishing agents stored inside. Explicit dynamics simulations in ANSYS Workbench 2024 R2 were conducted by varying tube thickness from 0.5 mm to 2.0 mm to evaluate the structural response of adjacent components. Three indices were examined: total deformation, deformation of the adjacent plate, and deformation of the tube itself. The results showed that thinner tubes (0.5 mm) allowed for greater propagation of blast energy, increasing the risk of damage, whereas thicker tubes (≥1.5 mm) effectively confined the explosive energy and reduced shock transmission. These findings confirm that tube thickness is a key parameter governing blast-induced deformation, with 1.5 mm identified as the threshold for minimizing structural damage. This study provides practical design guidelines for polymer-based automatic suppression systems, contributing to safer fire protection solutions for electric vehicles and related industrial applications. Full article

The rising cost of traditional energy sources is forcing us to seek alternatives that enable energy self-sufficiency. At the Madrid Zoo Aquarium (Spain), the production of biomethane through the anaerobic digestion of organic waste is being considered, improving environmental management and achieving a competitive advantage in the energy management process. This opportunity also carries with it the possibility of explosions, fires or polluting environments, which requires the establishment of preventive measures to minimize these risks. To respond to this type of contingency, this study develops both empirical equation and charts that allow the establishment of dangerous distances that must be considered due to the presence of flammable gases escaping into the atmosphere and the duration of the danger, taking into account the influence of environmental conditions and dilution. Different risk situations are considered, both during the operation of the facility and during the cleaning and maintenance of tanks and equipment, as well as in the management of waste generated at the end of treatment. Full article

Fossil fuel-based power production faces challenges, particularly greenhouse gas emissions, that contribute to global warming. This paper explores retrofitting an existing 207.8 MW coal-fired steam power unit with a Concentrated Solar Power (CSP) tower system and Thermal Energy Storage (TES) systems to create a hybrid solar–coal power plant. The concept integrates a solar component and a two-tank TES system into the existing steam Rankine cycle. Thermodynamic modeling and balance calculations were performed using Ebsilon Professional software (version 16) to analyze the design. Three injection points for feedwater preheating were analyzed, with flow rates that varied from 10 to 100 kg/s. Thermodynamic simulations show that solar contributions of 16.0 MW (Variant 1), 27.6 MW (Variant 2), and 37.6 MW (Variant 3) increase net electricity output to 213.5 MW, 216.8 MW, and 219.3 MW, respectively. The corresponding thermal efficiencies rise from 42.6% to 43.8%, while the hybrid system’s total efficiency improves up to 29.6%. These results demonstrate that controlled feedwater diversion and solar integration can enhance performance, reduce coal dependency, and lower CO₂ emissions without compromising operational stability. Full article