Leakage Accidents Research Articles

Quantitative assessment of human error of emergency behavior for hazardous chemical spills in chemical parks

In-depth research on human error is of great significance to improve the human reliability in the emergency rescue as well as to avoid the occurrence of secondary accidents. Therefore, the standardized process and key emergency behaviors in the emergency rescue process of hazardous chemical leakage accidents are first analyzed. Based on the Cognitive Reliability and Error Analysis Method, the human error mode was sorted out, and the human error probability estimation model was established. Combining the improved Analytic Hierarchy Process and entropy weight method, a model for estimating the severity of human error was established, realizing the quantitative analysis of the human reliability of the emergency behavior. The study showed that the 21 emergency behaviors were clustered into 3 categories, with clustering 1 including 2 emergency behaviors, which have the highest level of severity, clustering 2 including 11 emergency behaviors, and clustering 3 including 8 emergency behaviors. Finally, countermeasures were proposed in four areas, including increasing the level of Common Performance Conditions and the ability to transmit information on accidents, etc. It indicates that the method can widely guide the improvement of emergency response capability in chemical parks.

Burning behavior of hydrogen jet flame inhibited by a wire mesh screen

Hydrogen is recognized as a promising energy source and the potential risks associated with leakage and jet fire accidents should be considered. The objective of this study is to explore the feasibility of utilizing wire mesh to suppress hydrogen jet flames. The experiments of hydrogen jet fire with ignitors below and above the wire mesh were performed to explore the effect of wire mesh on the burning behaviors at different mesh numbers, mesh-to-nozzle distances, and fuel flow rates. Compared to the free jet flame, the length of jet flame under the action of wire mesh is decreased by 50–90 %. The flame with topside ignition fails to pass through the mire mesh due to the cooling effect of the fuel jet. Experimental results reveal that the state of the flow field in the impingement area plays an important role in determining the upper flame height. Both the upper flame height and the flame extension length beneath the screen decrease with mesh-to-nozzle distance. As the mesh porosity decreases, the flame extension length increases, however, the upper flame height decreases. Based on the classical theory of flow resistance through porous media, a new dimensionless model was developed to predict the characteristic flame lengths of the jet flame inhibited by wire mesh. The findings presented in this paper offer fresh insight into the safeguarding of jet fires.

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.

Hydrogen Jet Flame Simulation and Thermal Radiation Damage Estimation for Leakage Accidents in a Hydrogen Refueling Station

With the rapid development of hydrogen energy worldwide, the number of hydrogen energy facilities, such as hydrogen refueling stations, has grown rapidly in recent years. However, hydrogen is prone to leakage accidents during use, which could lead to hazards such as fires and explosions. Therefore, research on the safety of hydrogen energy facilities is crucial. In this paper, a study of high-pressure hydrogen jet flame accidents is conducted for a proposed integrated hydrogen production and refueling station in China. The effects of leakage direction and leakage port diameter on the jet flame characteristics are analyzed, and a risk assessment of the flame accident is conducted. The results showed that the death range perpendicular to the flame direction increased from 2.23 m to 5.5 m when the diameter of the leakage port increased from 4 mm to 10 mm. When the diameter of the leakage port is larger than 8 mm, the equipment on the scene will be within the boundaries of the damage. The consequences of fire can be effectively mitigated by a reasonable firewall setup to ensure the overall safety of the integrated station.

Research on fence protection for liquid hydrogen leakage in the storage tank area

Hydrogen energy is an important carrier for energy terminals to achieve green and low-carbon transformation, but hydrogen safety remains a bottleneck for its large-scale commercial development. This study conducts numerical simulation of hydrogen leakage accidents in liquid hydrogen refueling stations, analyzes the shortcomings of protective walls in the safety aspect, and proposes the use of fences for protection. The results show that although the protective walls can prevent the cold hydrogen gas from diffusing outside the storage tank area, it greatly increases the duration and final dissipation time. Then gas cloud is prone to accumulate in corners. The fences can alter the turbulent field around the storage tank area, accelerate the heat exchange between cloud and air, and promote buoyancy. The promoting effect of fences on turbulence is most evident under windy conditions, especially outside the fence. Results indicate that the 3 cm and 4 cm fences have the best effect. Compared with the protective wall case, under windy conditions, the dissipation time of flammable clouds in the corner of the 3 cm fence is reduced by 8 s, while the 4 cm fence is reduced by 7 s. It should be noted that under wind conditions, the dilution time outside the 3 cm fence decreases by 21 s, while the 4 cm fence decreases by 35 s. Under windy conditions, there is a uniformly concentrated strong turbulent flow field near the 3 cm fence.

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.

Research on the hydraulic parameters and leak rate of natural gas flow in natural gas pipelines based on the methods of characteristic line and successive approximation

Pressure and flow rate are the most important hydraulic parameters in natural gas pipeline flow, and leak rate is the most crucial parameter after a leak accident occurs. The study of these parameters is vital to the safey of natural gas pipelines and risk assessment after accidents. In this research, based on the conservation laws universally applicable to the motion of objects, we establish the fundamental control equation group for natural gas flow. Then, for both normal and leak conditions of pipelines, we use the characteristic line method to derive the corresponding difference equations for the fundamental control equations, thereby providing calculation methods for pressure and flow rate. Finally, we investigate the calculation method of natural gas pipeline leak rate under different leak aperture sizes, and validate the accuracy of this method through simulation examples.

Analysis of China's Economic and Trade Policy Changes and Future Trends of Japan under the Influence of Japanese Nuclear Sewage Incident—— The Marxist National Security Theory Based on Sinicization

On August 24, 2023, the Japanese government officially discharged the nuclear sewage stored in the Fukushima nuclear leakage accident into the sea to alleviate the overload situation of water storage pressure in relevant facilities. This approach directly brings great risks to the safety of the Marine environment and biological resources in the surrounding areas of Japan, and is more likely to seriously endanger the life safety and health of the people in the neighboring countries. Faced with this situation, China always adheres to the Chinese Marxist theory of national security and follows a holistic approach to national security. It adjusts its foreign policy based on the actual situation at home and abroad and takes targeted measures to adapt to the global situation. China firmly safeguards its national security and the interests of its people, providing new ideas and approaches to the international community and promoting a constructive approach to international relations.

Evaluation method investigation of public decontamination time in off-site nuclear emergency under the influence of human factors

Decontamination is an important means to reduce the personnel radioactive contamination under sever nuclear accidents. Public decontamination time estimation with the process simulation is helpful for emergency organizations to improve efficiency. To date, most studies focus on improving personal decontamination technology and decontamination strategies, while research on the overall decontamination process and time estimating is limited. Due to the complex population structure, the unknown contaminated proportion and the complicated psychological emotions, it is hard to quantify the decontamination process and calculate the decontamination time with numerous procedures and diverse facility configurations. Combined with public contaminated proportion, crowd structure and waiting psychology, a public decontamination model based on queuing theory and system dynamics method is established for offsite nuclear emergency to simulate the decontamination process and give an estimate of decontamination time. A hypothetical nuclear leakage accident of Changjiang Nuclear Power Plant in Hainan, China is conducted to simulate the established model. The results show the working status of different facilities at different stages and the changes in waiting queues at different times, which can effectively calculate the duration time of each link and the overall public decontamination progress. A plan for adding devices is provided to meet the decontamination time requirements and control the number of waiting queues within the specified threshold efficiently. The method proposed in this paper could help nuclear emergency decision-makers estimate the public decontamination time, optimize site configuration plans, give guidance on public decontamination procedures and prepare for the subsequent nuclear emergency evacuation.

Experimental investigation of the characteristics of flame geometry and heat transfer from wind-driven pool fires

Wind-driven pool fire is a frequently encountered thermal hazard in cases of liquid fuel leakage accidents. Given the intricate interplay between wind flow and thermal buoyancy, understanding the flame geometry and external heat transfer behavior of pool fires is vital for effective liquid fuel security management. This paper presents a study to investigate these characteristics under various square pool sizes (side length, D = 0.31, 0.38, 0.44, 0.49, and 0.54 m) and wind speeds (u = 0, 0.5, 1, 2, 4, and 6 m/s). Five parameters pertaining to global flame geometry and two parameters concerning external heat transfer were measured. The findings indicate that the change rate of overall flame geometry parameters accelerates at first and then decelerates with wind speed. The ratio of the net flame horizontal length dominated by inertia force (Li) and the net flame horizontal length dominated by buoyancy force (Lb) to the total horizontal flame length (Lh) (Li / Lh and Lb / Lh) present a non-monotonic trend with increasing Fr number. To further comprehend the global flame geometry, a corresponding physical model is developed based on the ratio of Grs number to the 5/2 power of Rem number (Grs / Rem5/2). Due to the effects of flame thickness and flame attachment length, the variation in radiant heat transfer with wind speed can be bifurcated into two categories. The convective heat coefficient increases with wind speed, enhancing the local convection. Finally, the new models of radiant and convective heat transfers are established using dimensionless wind speed (u*, u∗=u(ṁ″g/ρ0)1/3) and Ri number. To ascertain the suitability of these new models, they have been validated against two classic flame models.

Risk assessment and simulation of gas pipeline leakage based on Markov chain theory

Gas pipeline leakage may lead to fire, explosion and gas poisoning, thus causing a large number of injuries and property damage. This paper focuses on the chain characteristics presented by the development process of city gas pipeline leakage, based on Markov chain theory, studies the disaster-causing process and the mechanism of disaster chain formation for the leakage, establishes the disaster chain, evaluates the pipeline operation status and quantifies the failure probability of gas pipeline leakage to determine the causes of the leakage. Subsequently, Pipeline Studio is applied to simulate the consequences of gas pipeline leakage to realize the risk analysis. The analysis is based on Markov chain theory to calculate the probability of leakage and disaster-causing causes, analyze the consequences of gas pipeline leakage, and realize the diagnosis of the causes of gas pipeline leakage accidents and the prediction of the accident development trend. Finally, using European gas pipeline accident data to prove the effectiveness of the method, the result shows that gas pipeline leakage accidents are mainly caused by third-party damage and corrosion, which is consistent with the real situation and provides a reference for risk analysis and accident prevention of gas pipeline leakage.

Numerical simulation and experimental study of three-phase distribution characteristics of leaked light non-aqueous phase liquid from buried pipelines in soils containing groundwater and gas.

Leakage accidents of buried pipelines have become increasingly common due to the prolonged service of some pipelines which have been in use for more than 150years. Therefore, there is an urgent need for accurate prediction of pollution scope to aid in the development of emergency remediation strategies. This study investigated the distribution of a light non-aqueous phase liquid in soils containing gas and water through numerical simulations and laboratory experiments. Firstly, a three-dimensional porous medium model was established using ANSYS FLUENT, and for the first time, the distribution of gas and groundwater in soil environments was simulated in the model. Subsequently, the distribution of the three phases of diesel, gas, and water in soil was studied with different leakage velocities and it was found that the leakage velocity played a significant role in the distribution. The areas of diesel in soils at 60min were 0.112m2, 0.194m2, 0.217m2, and 0.252m2, with corresponding volumes of 0.028m3, 0.070m3, 0.086m3, and 0.106m3, respectively, for leakage velocities of 1.3m/s, 3.4m/s, 4.6m/s, and 4.9m/s. Calculation formulas for distribution areas and volumes were also developed to aid in future prevention and control strategies under different leakage velocities. The study also compared the distribution areas and volumes of diesel in soils with and without groundwater, and it was found that distribution scopes were larger in soils containing groundwater due to capillary force. In order to validate the accuracy of the numerical simulation, laboratory experiments were conducted to study the diffusion of oil, gas, and water under different leakage velocities. The results showed good agreement between the experiments and the simulations. The research findings are of great significance for preventing soil pollution and provide a theoretical basis for developing scientifically sound soil remediation strategies.

Kaolin-Derived Porous Silico-Aluminate Nanoparticles as Absorbents for Emergency Disposal of Toluene Leakage.

To rapidly eliminate toluene from aqueous environments during leakage accidents, this paper synthesized porous silico-aluminate nanoparticles (SANs) via a hydrothermal method, using cost-effective and non-toxic natural kaolin as the basic raw material. The morphology and structure of the porous SANs were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and BET-specific surface area tests. The effects of different conditions, such as the dosage of porous SANs, initial concentration of toluene, temperature, capture time, and pH, on the adsorption performance of porous SANs were analyzed. The as-prepared SANs exhibited a high removal efficiency and rapid adsorption performance toward toluene in aqueous solution. Finally, the kinetics of the adsorption of toluene in aqueous solution by porous SANs were investigated. The mechanism of the adsorption of toluene by porous SANs was further discussed. These findings provide a cost-effective and highly efficient absorbent for the emergency disposal of toluene leakage accidents.

Analysis of the Impact of Disposal of Oil-Contaminated Ballast Water on Marine Pollution in MT. Bull Kangean

Abstract Ballast water refers to water containing substances, materials, or goods necessary for ship stability, trim control, list (tilt), or pressure. According to the shipping terms dictionary, ballast can also include waste or refuse stored on board. This study aims to analyze the environmental impact of oil-contaminated ballast water disposal on marine pollution in MT. Bull Kangean. Oil spills at sea typically occur due to two reasons: accidental leaks caused by damage to the ship hull or oil tanks (e.g., collisions with coral reefs or sunken objects), and deliberate discharge of used oil from manufacturing equipment, which can lead to environmental contamination and harm to areas designated for oil disposal. The research methodology involves collecting primary data through observations, interviews, and document reviews to understand the impact of oil-contaminated ballast water disposal on marine pollution. Qualitative descriptive methods are employed for data analysis. The findings of this research indicate that the disposal of oil-contaminated ballast water does result in marine pollution. Observations reveal that inadequate supervision by the deck crew regarding ballast water disposal leads to the mixing of oil with the water during the disposal process.

40‐4: Improving Visibility Coherence between Auto Macro Inspection and Auto Visual Inspection Using AI Image Translation

In OLED production, the glass fabrication process is prone to frequent occurrences of persistent mura defects, leading to significant damage in the event of defects, as the subsequent final inspection, AVI (Auto Visual Inspection), is time‐consuming. Therefore, there is a need for a consistent inspection. Currently, manual inspection by operators introduces variations in inspection criteria among individuals, resulting in ongoing challenges related to false judgments and post‐process leakage issues The invested automated inspection system for quantitative determination is utilized as a reference only, as the distinction between pseudo‐defects deemed acceptable in AVI and true defects identified as faulty in AVI poses limitations with the traditional logic‐based inspection methods. We enhanced the mura visibility of automatic inspection system (Auto Macro) images through pre‐processing, followed by translation into an image environment similar to AVI images using Pix2pix GAN. Subsequently, we compared the mura index extracted from the processed images with the AVI mura index for evaluation. The Auto Macro images transformed by Pix2pix GAN exhibited similarities with AVI images in terms of overall luminance, gray distribution, and mura visibility intensity. Consequently, the R‐Squared correlation between the mura index of Auto Macro and AVI improved from 0.00 to 0.68. Additionally, defects unrecognized in AVI during Auto Macro inspection were automatically eliminated. False defects in the Auto Macro test that were not recognized in AVI were automatically removed. In this study, we applied the AI model to the Auto Macro inspection system to overcome the limitations of logic‐based inspections. We proposed a method to proactively detect defect‐induced muras before cell‐level processing, aiming to improve yield and reduce incidents of customer leakage accidents.

A plasma partial oxidation approach for removal of leaked LPG in confined spaces

Effective removal of leaked Liquefied petroleum gas (LPG) in poorly ventilated confined spaces remains a huge challenge in emergency response. In this paper, a plasma partial oxidation (PPO) approach was proposed to remove the leaked hazardous gases in confined spaces. A double dielectric barrier discharge (DDBD) reactor with a discharge volume of 13.56 ml was used at an initial Butane (simulate LPG) concentration of 5 % to study the effects of discharge power, gas flow rate and its co-action on the reaction performance, and the feasibility of the removal approach was demonstrated. The main hazardous gases in the exhaust are Butane and CO. By establishing the functional relationship of Butane concentration and CO concentration to energy density, it was calculated that the 5 % initial Butane concentration can be reduced to less than 1.9 % when the energy density (discharge power/gas flow rate) reaches 2.17 kJ/L, which eliminates the explosion risk of leaking Butane, and at the same time, the CO concentration is 0.8 %, which has a low CO toxicity. This paper provides a new approach for removing leaked LPG, which is expected to be practically applied in the disposal of hazardous gas leakage accidents in confined spaces.

Leakage Source Location of Hazardous Chemicals Based on the Improved Gray Wolf Optimization Algorithm

To accurately determine the leakage source location and strength during gas leakage accidents, this study compares the concentration obtained from the diffusion model with that measured by the sensor and proposes an improved gray wolf optimization algorithm for leakage source location. This algorithm introduces two improvement strategies. First, a nonlinear convergence factor is introduced to balance the global and local searches of the algorithm. Second, a reverse learning operation is performed on the three individuals with the worst fitness in the contemporary population. The results showed that the location results based on the improved gray wolf optimization algorithm exhibited high accuracy and stability, could quickly and accurately locate the leakage source, and provided data support for emergency disposal of accidents.

Quantitative risk assessment of leakage accident of crude oil storage tank based on fuzzy Bayesian network and improved AHP

Leakage accidents of crude oil storage tanks (LACOST) occasionally occur during the production and storage processes of the petroleum and chemical industry, significantly impacting lives, the environment, and private property. To enhance the risk assessment of LACOST, our study sought to construct a fuzzy Bayesian network (FBN) through expert evaluation based on an improved analytic hierarchy process (AHP). Subsequently, the societal risk of LACOST was analyzed in conjunction with the surrounding population density. Applying the proposed method to a crude oil storage depot in China revealed that incorporating the improved AHP significantly enhances the FBN's risk assessment capability, leading to more accurate predictions of LACOST likelihood. Furthermore, the importance of basic events was assessed, thereby effectively and reliably identifying critical events of LACOST. The rationality of the layout of buildings and population density in the oil depot was assessed through societal risk analysis. Collectively, our findings demonstrated that the proposed method can effectively identify changes in both LACOST probabilities and consequences, enabling decision-makers to optimize risk management strategies and achieve efficient resource allocation.

Performance and mechanism of DL‐alanine ionic liquid shale inhibitor

AbstractShale hydration and expansion during drilling can lead to wellbore instability, sticking, and frequent leakage accidents. To prevent these issues, an ionic liquid (IL) inhibitor solution was synthesized using DL‐alanine and 98% concentrated sulphuric acid as raw materials. The optimum composition and effect of the synthesized inhibitor in oilfield water‐based drilling fluids were evaluated through anti‐expansion, linear expansion rate, water washing resistance, and clay hydration dispersion experiments. The inhibition mechanism was investigated by thermogravimetric analysis, infrared spectroscopy, zeta potential, contact angle, and X‐ray diffraction analysis. The results show that the optimum IL consists of a 1:1 molar ratio of DL‐alanine to concentrated sulphuric acid synthesized under a reaction temperature and time of 70°C and 18 h, respectively. The resulting DL‐alanine IL exhibited the best inhibitory effect on the hydration, dispersion, and expansion of clay at a concentration of 0.5% in aqueous solution, and its linear expansion rate was only 18.49%. After adding a quantitative amount of clay to different concentrations of DL‐alanine IL aqueous solution, the expansion volume of the clay decreased and the water washing resistance significantly improved. These results provide a theoretical basis for improving the safety and efficiency of shale horizontal well drilling operations.

Experimental study on the characteristics of buoyant gas flow produced by vertical gas leakage in tunnels under natural ventilation

In recent years, there have been reports of gas leakage accidents during the transportation of gas tankers in tunnels, potentially leading to destructive explosions. However, the overall distribution of gas concentration in the entire tunnel has not been experimentally investigated. This study presents a series of brine-water experiments to explore the characteristics of buoyant gas flow in tunnel leakage accidents. The gas distribution is categorized into a stably stratified longitudinal current and a source region. Gas concentration in the tunnel is correlated with the dimensionless reduced gravity, which increases with the source buoyancy flux but decreases with the source release velocity. A model is proposed to estimate the maximum gas concentration of the longitudinal current. The spatial range of the explosive region is influenced by the source buoyancy flux and the leakage velocity. However, the propagation velocity of the longitudinal current is primarily controlled by the source buoyancy flux, with the source momentum having a negligible effect. The thickness of the longitudinal gas flow, δ, linearly decreases from the source region to the tunnel ends. A dimensionless parameter, λ, is introduced to characterize δ. When λ < 1.25, δ rapidly increases with λ and then remains approximately constant when λ exceeds 1.25. This study contributes to a better understanding of buoyant gas flow in tunnel leakage accidents.