Pub Date : 2025-01-09DOI: 10.1016/j.jlp.2025.105543
Fateme Rashidi, Soroush Baradaran, Mohammad Amin Sobati
The study presents a novel comprehensive approach for quantitative dynamic risk assessment in the reaction section of a biodiesel production plant. The methodology combines sequential established techniques (HAZOP analysis, Bow-Tie (BT) analysis) with a Fuzzy Bayesian Network (FBN) in process safety assessment of biodiesel production. Following a thorough process hazard identification, detailed design gaps were addressed and modified. Dynamic risk assessment was then performed by combining the BN with fuzzy approach to cover the limitations of conventional risk analysis and to deal with the uncertainty in the modeling due to lack of credible equipment failure rate data. Assessment on the effectiveness of design improvement revealed a substantial 90% risk reduction following the implementation of technical recommendations obtained from the HAZOP analysis. Sensitivity analysis using the FBN also revealed the reactor pressure transmitter and safety valves as the critical safety elements of the process. Implementing design modifications based on such analysis reduced the risk level by 95%. This study highlights the effective combination of the established methods with FBN for dynamic risk assessment and targeted design improvements, ultimately leading to enhanced safety in biodiesel production plants.
{"title":"Design improvement for enhanced process safety in a biodiesel production unit using Fuzzy Bayesian network analysis","authors":"Fateme Rashidi, Soroush Baradaran, Mohammad Amin Sobati","doi":"10.1016/j.jlp.2025.105543","DOIUrl":"10.1016/j.jlp.2025.105543","url":null,"abstract":"<div><div>The study presents a novel comprehensive approach for quantitative dynamic risk assessment in the reaction section of a biodiesel production plant. The methodology combines sequential established techniques (HAZOP analysis, Bow-Tie (BT) analysis) with a Fuzzy Bayesian Network (FBN) in process safety assessment of biodiesel production. Following a thorough process hazard identification, detailed design gaps were addressed and modified. Dynamic risk assessment was then performed by combining the BN with fuzzy approach to cover the limitations of conventional risk analysis and to deal with the uncertainty in the modeling due to lack of credible equipment failure rate data. Assessment on the effectiveness of design improvement revealed a substantial 90% risk reduction following the implementation of technical recommendations obtained from the HAZOP analysis. Sensitivity analysis using the FBN also revealed the reactor pressure transmitter and safety valves as the critical safety elements of the process. Implementing design modifications based on such analysis reduced the risk level by 95%. This study highlights the effective combination of the established methods with FBN for dynamic risk assessment and targeted design improvements, ultimately leading to enhanced safety in biodiesel production plants.</div></div>","PeriodicalId":16291,"journal":{"name":"Journal of Loss Prevention in The Process Industries","volume":"94 ","pages":"Article 105543"},"PeriodicalIF":3.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-09DOI: 10.1016/j.jlp.2025.105552
Hana Vykopalová
Psychosocial risks and assessment of psychosocial risk factors in working conditions are current issues affecting the level of mental health in connection with the performance of workers in all work areas. Stress theory, stress and the importance of exposure to psychosocial risks as basic research starting points and connections to working conditions, mental health. Effects of stress on learning and memory processes. Cognitive processes and cognitive distortions, the incidence of error and their influence on the reliability of the human factor. The importance of ambivalence on risk perception. The effects of distress, the role of defence mechanisms and alexithymia and their manifestations in the workplace, the transformation of risk stressors in working conditions, as less well-known dissatisfactions. Alarming findings in the area of the prevalence and sharp increase of mental illnesses recently as a result of social isolation (Covid 19 pandemic), but also workload due to increasingly advanced technologies and digitization of work activities.
{"title":"Prevalence of psychosocial risk severity, stress and cognitive dissonance in working conditions","authors":"Hana Vykopalová","doi":"10.1016/j.jlp.2025.105552","DOIUrl":"10.1016/j.jlp.2025.105552","url":null,"abstract":"<div><div>Psychosocial risks and assessment of psychosocial risk factors in working conditions are current issues affecting the level of mental health in connection with the performance of workers in all work areas. Stress theory, stress and the importance of exposure to psychosocial risks as basic research starting points and connections to working conditions, mental health. Effects of stress on learning and memory processes. Cognitive processes and cognitive distortions, the incidence of error and their influence on the reliability of the human factor. The importance of ambivalence on risk perception. The effects of distress, the role of defence mechanisms and alexithymia and their manifestations in the workplace, the transformation of risk stressors in working conditions, as less well-known dissatisfactions. Alarming findings in the area of the prevalence and sharp increase of mental illnesses recently as a result of social isolation (Covid 19 pandemic), but also workload due to increasingly advanced technologies and digitization of work activities.</div></div>","PeriodicalId":16291,"journal":{"name":"Journal of Loss Prevention in The Process Industries","volume":"94 ","pages":"Article 105552"},"PeriodicalIF":3.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-09DOI: 10.1016/j.jlp.2025.105551
Miroslav Mynarz , Aleš Tulach , Marian Bojko
Quantification of time and spatial concentration profiles of a gas-air cloud caused by accidental leakage of flammable gas from damaged equipment can be of great importance for the correct prediction of the occurrence of dangerous situations. Knowing the extent of leakage and time dependence of generation of hazardous concentrations may be a good tool in the design of mitigation equipment (e.g., gas detection alarms) or in determining further measures (e.g., the extent and method of ventilation of the premises).
The paper describes the dispersion of leaked methane (natural gas) from a damaged low-pressure gas pipeline, in a confined space with a geometrically complex environment and the formation of local explosive concentrations at the lower explosion limit (LEL) of the methane-air mixture. The measurements were carried out in a middle-scale model of a building with a volume of approximately 2.7 m3. A new type of sensing system has been developed for the detection of individual concentrations, allowing the required concentrations to be recorded continuously and with greater accuracy.
The velocity of propagation of leaked gas, local explosive concentrations of a gas-air mixture, and also duration of formations of these local concentrations, could be determined using successful verification of a CFD simulation with experiments. A comparison of experimental data with simulation data demonstrated that CFD technology can be an effective aid to describe the process of flammable gas dispersion and can also predict the tendency of gas dispersion and gas distribution. The key to a successful application of CFD in dispersion simulation lies in the accuracy with which the effect of turbulence is generated, due to the complex geometry of the monitored space. Within the simulations of turbulent flow, the accordance of experimentally determined values with the values calculated in dependence on the mesh density and used turbulence model was observed. RANS equations with six turbulent models were used (Laminar; k-ε Standard; k-ε RNG; k-ε Realizable; k-ω Standard and k-ω SST). The best match of the numerical simulation results with the performed experiments was achieved using the mathematical model of turbulence k-ε RNG.
{"title":"CFD-based simulation of flammable gas dispersion in a complex geometry","authors":"Miroslav Mynarz , Aleš Tulach , Marian Bojko","doi":"10.1016/j.jlp.2025.105551","DOIUrl":"10.1016/j.jlp.2025.105551","url":null,"abstract":"<div><div>Quantification of time and spatial concentration profiles of a gas-air cloud caused by accidental leakage of flammable gas from damaged equipment can be of great importance for the correct prediction of the occurrence of dangerous situations. Knowing the extent of leakage and time dependence of generation of hazardous concentrations may be a good tool in the design of mitigation equipment (e.g., gas detection alarms) or in determining further measures (e.g., the extent and method of ventilation of the premises).</div><div>The paper describes the dispersion of leaked methane (natural gas) from a damaged low-pressure gas pipeline, in a confined space with a geometrically complex environment and the formation of local explosive concentrations at the lower explosion limit (LEL) of the methane-air mixture. The measurements were carried out in a middle-scale model of a building with a volume of approximately 2.7 m<sup>3</sup>. A new type of sensing system has been developed for the detection of individual concentrations, allowing the required concentrations to be recorded continuously and with greater accuracy.</div><div>The velocity of propagation of leaked gas, local explosive concentrations of a gas-air mixture, and also duration of formations of these local concentrations, could be determined using successful verification of a CFD simulation with experiments. A comparison of experimental data with simulation data demonstrated that CFD technology can be an effective aid to describe the process of flammable gas dispersion and can also predict the tendency of gas dispersion and gas distribution. The key to a successful application of CFD in dispersion simulation lies in the accuracy with which the effect of turbulence is generated, due to the complex geometry of the monitored space. Within the simulations of turbulent flow, the accordance of experimentally determined values with the values calculated in dependence on the mesh density and used turbulence model was observed. RANS equations with six turbulent models were used (Laminar; k-ε Standard; k-ε RNG; k-ε Realizable; k-ω Standard and k-ω SST). The best match of the numerical simulation results with the performed experiments was achieved using the mathematical model of turbulence k-ε RNG.</div></div>","PeriodicalId":16291,"journal":{"name":"Journal of Loss Prevention in The Process Industries","volume":"94 ","pages":"Article 105551"},"PeriodicalIF":3.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-09DOI: 10.1016/j.jlp.2025.105550
Ramon Swell Gomes Rodrigues Casado , Marcelo Hazin Alencar , Adiel Teixeira de Almeida
Considering the dense network of natural gas pipelines, gas transportation companies face the dilemma of maintaining a profitable operation while ensuring efficient risk management. The inherent uncertainties in risk assessment and the need for well-founded strategic decisions further exacerbate this challenge. To address these issues, the paper proposes a risk-based portfolio selection approach, incorporating global sensitivity analysis, which helps prioritize high-risk areas for pipeline maintenance and integrity. As a result, this approach optimizes resource allocation and ensures better allocation to the most critical areas. The main innovation of the study lies in developing a robust methodology that guides actions in the natural gas transportation system, handling uncertainties, and considering both safety concerns and organizational constraints. The developed model is divided into three parts. The first part uses a multidimensional risk assessment methodology to evaluate the consequences across three dimensions: environmental, financial, and human. These dimensions are associated with potential accidents caused by pipeline leaks and their impacts. The second part employs a hybrid search algorithm to select the most critical sections of the pipeline portfolio. The last part uses Monte Carlo simulation to comprehensively analyze the uncertainties involved in risk assessment. A case study is presented to validate the proposed methodology. Based on the results, the approach offers more reliable decision-making when selecting the most critical zones, and decision sensitivity levels are statistically estimated for each pipeline section. This information guides managers in efficiently allocating resources to mitigate losses and maintain operational integrity. Thus, the proposed structured procedure decisively supports risk management in natural gas transportation and guides strategic decisions.
{"title":"Exploring risk-based portfolio selection with global sensitivity analysis to support strategic decisions in natural gas pipeline networks","authors":"Ramon Swell Gomes Rodrigues Casado , Marcelo Hazin Alencar , Adiel Teixeira de Almeida","doi":"10.1016/j.jlp.2025.105550","DOIUrl":"10.1016/j.jlp.2025.105550","url":null,"abstract":"<div><div>Considering the dense network of natural gas pipelines, gas transportation companies face the dilemma of maintaining a profitable operation while ensuring efficient risk management. The inherent uncertainties in risk assessment and the need for well-founded strategic decisions further exacerbate this challenge. To address these issues, the paper proposes a risk-based portfolio selection approach, incorporating global sensitivity analysis, which helps prioritize high-risk areas for pipeline maintenance and integrity. As a result, this approach optimizes resource allocation and ensures better allocation to the most critical areas. The main innovation of the study lies in developing a robust methodology that guides actions in the natural gas transportation system, handling uncertainties, and considering both safety concerns and organizational constraints. The developed model is divided into three parts. The first part uses a multidimensional risk assessment methodology to evaluate the consequences across three dimensions: environmental, financial, and human. These dimensions are associated with potential accidents caused by pipeline leaks and their impacts. The second part employs a hybrid search algorithm to select the most critical sections of the pipeline portfolio. The last part uses Monte Carlo simulation to comprehensively analyze the uncertainties involved in risk assessment. A case study is presented to validate the proposed methodology. Based on the results, the approach offers more reliable decision-making when selecting the most critical zones, and decision sensitivity levels are statistically estimated for each pipeline section. This information guides managers in efficiently allocating resources to mitigate losses and maintain operational integrity. Thus, the proposed structured procedure decisively supports risk management in natural gas transportation and guides strategic decisions.</div></div>","PeriodicalId":16291,"journal":{"name":"Journal of Loss Prevention in The Process Industries","volume":"94 ","pages":"Article 105550"},"PeriodicalIF":3.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-08DOI: 10.1016/j.jlp.2025.105545
Leonardo Leoni , John Andrews , Filippo De Carlo
Fault Tree (FT) Analysis is still one of the most common approaches for conducting reliability analysis of complex systems. However, it conceals several limitations such as the assumption of independent events and inability to model modern maintenance strategies in its basic form. To enhance FT analysis and overcome these limitations, Dynamic and Dependent Tree Theory, , has been recently introduced. This algorithm is based on the integration of Petri Nets, Markov models, and Binary Decision Diagram with the FT. Despite its effectiveness, its generalizability for different case studies needs to be explored. This is especially true for the application to safety barriers, which spend most of their time in a standby state. Thus, this paper aims to provide an extension of the approach to further prove its capabilities and adopt it for safety barriers. To this end, the framework is applied to an offshore fire deluge system considering an availability analysis and a reliability analysis for the standby and operational phase respectively. The proposed modified framework could be used by maintenance engineers and managers to conduct reliability analysis of safety barriers, along with testing multiple maintenance strategies for their components.
{"title":"Extending the dynamic and dependent tree theory (D2T2) to safety barriers: An application to an offshore fire deluge system","authors":"Leonardo Leoni , John Andrews , Filippo De Carlo","doi":"10.1016/j.jlp.2025.105545","DOIUrl":"10.1016/j.jlp.2025.105545","url":null,"abstract":"<div><div>Fault Tree (FT) Analysis is still one of the most common approaches for conducting reliability analysis of complex systems. However, it conceals several limitations such as the assumption of independent events and inability to model modern maintenance strategies in its basic form. To enhance FT analysis and overcome these limitations, Dynamic and Dependent Tree Theory, <span><math><mrow><msup><mi>D</mi><mn>2</mn></msup><msup><mi>T</mi><mn>2</mn></msup></mrow></math></span>, has been recently introduced. This algorithm is based on the integration of Petri Nets, Markov models, and Binary Decision Diagram with the FT. Despite its effectiveness, its generalizability for different case studies needs to be explored. This is especially true for the application to safety barriers, which spend most of their time in a standby state. Thus, this paper aims to provide an extension of the <span><math><mrow><msup><mi>D</mi><mn>2</mn></msup><msup><mi>T</mi><mn>2</mn></msup></mrow></math></span> approach to further prove its capabilities and adopt it for safety barriers. To this end, the framework is applied to an offshore fire deluge system considering an availability analysis and a reliability analysis for the standby and operational phase respectively. The proposed modified framework could be used by maintenance engineers and managers to conduct reliability analysis of safety barriers, along with testing multiple maintenance strategies for their components.</div></div>","PeriodicalId":16291,"journal":{"name":"Journal of Loss Prevention in The Process Industries","volume":"94 ","pages":"Article 105545"},"PeriodicalIF":3.6,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-06DOI: 10.1016/j.jlp.2025.105548
Feng Li , Baoyan Duan , Chenyu Zhang , Chenchen Wang
Hazardous chemical storage, transport and refining enterprises involve significant quantities of toxic and harmful hazardous materials. These hazardous substances can lead to a series of accidents when they encounter ignition sources or undergo uncontrolled reactions. Such accidents involve various types of equipment and pipelines, potentially resulting in serious consequences, thus, the associated risks should not be overlooked. Consequently, a quantitative risk assessment of the N-decane storage and transportation process in an industrial area in Tianjin was conducted. Firstly, the types of equipment, along with their working pressures, are introduced. The likelihood of VCE resulting from leakage is determined based on the OGP database and delayed ignition probability model. Secondly, based on the numerical simulation and the experimental testing method, the diffusion and explosion characteristics of N-decane liquid mist are investigated, and the fitted curves of explosion overpressure on the pneumatic pressures are obtained, which, when combined with the injury probability model, allow for the determination of potential consequences. Finally, by integrating the VCE probability of equipment and their consequences with a risk classification matrix, a probabilistic risk assessment model is established. This model serves as a reference for the risk assessment system of other process units and equipment within the chemical industry.
{"title":"Probabilistic risk assessment of VCE for chemical equipment, case study: Storage and transportation process of N-decane","authors":"Feng Li , Baoyan Duan , Chenyu Zhang , Chenchen Wang","doi":"10.1016/j.jlp.2025.105548","DOIUrl":"10.1016/j.jlp.2025.105548","url":null,"abstract":"<div><div>Hazardous chemical storage, transport and refining enterprises involve significant quantities of toxic and harmful hazardous materials. These hazardous substances can lead to a series of accidents when they encounter ignition sources or undergo uncontrolled reactions. Such accidents involve various types of equipment and pipelines, potentially resulting in serious consequences, thus, the associated risks should not be overlooked. Consequently, a quantitative risk assessment of the N-decane storage and transportation process in an industrial area in Tianjin was conducted. Firstly, the types of equipment, along with their working pressures, are introduced. The likelihood of VCE resulting from leakage is determined based on the OGP database and delayed ignition probability model. Secondly, based on the numerical simulation and the experimental testing method, the diffusion and explosion characteristics of N-decane liquid mist are investigated, and the fitted curves of explosion overpressure on the pneumatic pressures are obtained, which, when combined with the injury probability model, allow for the determination of potential consequences. Finally, by integrating the VCE probability of equipment and their consequences with a risk classification matrix, a probabilistic risk assessment model is established. This model serves as a reference for the risk assessment system of other process units and equipment within the chemical industry.</div></div>","PeriodicalId":16291,"journal":{"name":"Journal of Loss Prevention in The Process Industries","volume":"94 ","pages":"Article 105548"},"PeriodicalIF":3.6,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-05DOI: 10.1016/j.jlp.2025.105547
Yan Wang , Zhitao Chen , Xiaoxiao Guo , Chongchong Cai , Jie Chen , Yang Su , Wentao Ji
A modification chemical inhibitor (phytic acid-modified Mg-Al hydrotalcite) was synthesized via using phytic acid to chelate metal ions. Mg-Al hydrotalcite was used as the base material, the phytic acid molecules were grafted onto the surface of Mg-Al hydrotalcite via self-assembly through coordination bonds. The effectiveness of phytic acid-modified Mg-Al hydrotalcite in the inhibition of polyethylene dust explosion was investigated. The results showed that phytic acid modification effectively upgraded the inhibition performance of original Mg-Al hydrotalcite. At the phytic acid-modified Mg-Al hydrotalcite inhibition ratio of 1.0, the reduction of maximum explosion pressure and maximum pressure rise rate increased by 21.51% and 26.83% respectively compared to original Mg-Al hydrotalcite. Combining the material characterization and thermal analysis, the inhibition mechanism of phytic acid-modified Mg-Al hydrotalcite on polyethylene dust explosion was deeply revealed. It is noticeable that phytic acid-modified Mg-Al hydrotalcite has a better chemical inhibition effect than original that. The research results provide a basis for preventing and controlling polyethylene dust explosion disasters, and offer a new insight for the development of novel explosion inhibition materials.
{"title":"Feasible approach to enhance inhibition performance of Mg-Al hydrotalcite on polyethylene dust explosion: Phytic-acid modification","authors":"Yan Wang , Zhitao Chen , Xiaoxiao Guo , Chongchong Cai , Jie Chen , Yang Su , Wentao Ji","doi":"10.1016/j.jlp.2025.105547","DOIUrl":"10.1016/j.jlp.2025.105547","url":null,"abstract":"<div><div>A modification chemical inhibitor (phytic acid-modified Mg-Al hydrotalcite) was synthesized via using phytic acid to chelate metal ions. Mg-Al hydrotalcite was used as the base material, the phytic acid molecules were grafted onto the surface of Mg-Al hydrotalcite via self-assembly through coordination bonds. The effectiveness of phytic acid-modified Mg-Al hydrotalcite in the inhibition of polyethylene dust explosion was investigated. The results showed that phytic acid modification effectively upgraded the inhibition performance of original Mg-Al hydrotalcite. At the phytic acid-modified Mg-Al hydrotalcite inhibition ratio of 1.0, the reduction of maximum explosion pressure and maximum pressure rise rate increased by 21.51% and 26.83% respectively compared to original Mg-Al hydrotalcite. Combining the material characterization and thermal analysis, the inhibition mechanism of phytic acid-modified Mg-Al hydrotalcite on polyethylene dust explosion was deeply revealed. It is noticeable that phytic acid-modified Mg-Al hydrotalcite has a better chemical inhibition effect than original that. The research results provide a basis for preventing and controlling polyethylene dust explosion disasters, and offer a new insight for the development of novel explosion inhibition materials.</div></div>","PeriodicalId":16291,"journal":{"name":"Journal of Loss Prevention in The Process Industries","volume":"94 ","pages":"Article 105547"},"PeriodicalIF":3.6,"publicationDate":"2025-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-04DOI: 10.1016/j.jlp.2025.105546
Shikai Huang , Jin Guo , Liang Mei , Fang Wang , Changjian Wang , Jin Lin
<div><div>Explosion venting technology is an effective means of reducing explosive hazards, and hydrogen volume fraction (χ) is one of the important parameters affecting its effectiveness. The vent covers, as a key part of the explosion venting application, consist of two types: inertia-free (e.g., membranes) and inertial (e.g., panels). χ has been extensively studied using inertial-free vent covers, but very limited work has been done using an inertial vent cover. Hence, the effects of χ, ranging from 0 to 1.0, on the vented H<sub>2</sub>/CH<sub>4</sub>/air explosion were studied in a chamber with a hinged aluminum panel, and the explosion overpressure during venting was simulated by FLACS software. The results show that the flame bubble becomes larger and brighter with increasing χ. However, the time for the flame to travel through the vent (<span><math><mrow><msub><mi>t</mi><mrow><mi>o</mi><mi>u</mi><mi>t</mi></mrow></msub></mrow></math></span>) and the opening angle of the hinged panel at the time of <span><math><mrow><msub><mi>t</mi><mrow><mi>o</mi><mi>u</mi><mi>t</mi></mrow></msub></mrow></math></span> constantly decreases as χ increases from 0 to 1.0. In the tests with χ ≤ 0.6, <span><math><mrow><msub><mi>p</mi><mn>3</mn></msub></mrow></math></span> caused by acoustically enhanced combustion becomes the pressure peak with the highest amplitude in the internal pressure profile, but the pressure peak <span><math><mrow><msub><mi>p</mi><mn>2</mn></msub></mrow></math></span> induced by the external explosion dominates the internal pressure trace for χ > 0.6. In comparison to the H<sub>2</sub>/CH<sub>4</sub>/air deflagration experiments using an inertialess vent cover, the shape of the external fireball is quite similar for smaller χ in the current study with an inertial vent panel. However, the use of the inertial vent panel results in a more flattened external fireball for larger χ. The highest amplitude of the external pressure peak (<span><math><mrow><msub><mi>p</mi><mrow><mi>e</mi><mi>x</mi><mi>t</mi></mrow></msub></mrow></math></span>) and the maximum reduced overpressure (<span><math><mrow><msub><mi>p</mi><mrow><mi>r</mi><mi>e</mi><mi>d</mi></mrow></msub></mrow></math></span>) increase with increasing χ. Whether the studies are performed with inertial and inertialess vent covers or FLACS simulations, the formation time (Δt) of <span><math><mrow><msub><mi>p</mi><mrow><mi>e</mi><mi>x</mi><mi>t</mi></mrow></msub></mrow></math></span> decreases linearly with increasing χ, but <span><math><mrow><msub><mi>p</mi><mrow><mi>r</mi><mi>e</mi><mi>d</mi></mrow></msub></mrow></math></span> increases linearly with <span><math><mrow><msubsup><mi>S</mi><mi>l</mi><mn>2</mn></msubsup></mrow></math></span>. The explosion overpressure simulated by FLACS is relatively close to the experimental results, and in particular, the simulated <span><math><mrow><msub><mi>p</mi><mrow><mi>r</mi><mi>e</mi><mi>d</mi></mrow></msub></mrow></math></span> agrees very well w
{"title":"Experiments on vented H2/CH4/air explosion in a chamber with a hinged panel: Effects of hydrogen volume fraction","authors":"Shikai Huang , Jin Guo , Liang Mei , Fang Wang , Changjian Wang , Jin Lin","doi":"10.1016/j.jlp.2025.105546","DOIUrl":"10.1016/j.jlp.2025.105546","url":null,"abstract":"<div><div>Explosion venting technology is an effective means of reducing explosive hazards, and hydrogen volume fraction (χ) is one of the important parameters affecting its effectiveness. The vent covers, as a key part of the explosion venting application, consist of two types: inertia-free (e.g., membranes) and inertial (e.g., panels). χ has been extensively studied using inertial-free vent covers, but very limited work has been done using an inertial vent cover. Hence, the effects of χ, ranging from 0 to 1.0, on the vented H<sub>2</sub>/CH<sub>4</sub>/air explosion were studied in a chamber with a hinged aluminum panel, and the explosion overpressure during venting was simulated by FLACS software. The results show that the flame bubble becomes larger and brighter with increasing χ. However, the time for the flame to travel through the vent (<span><math><mrow><msub><mi>t</mi><mrow><mi>o</mi><mi>u</mi><mi>t</mi></mrow></msub></mrow></math></span>) and the opening angle of the hinged panel at the time of <span><math><mrow><msub><mi>t</mi><mrow><mi>o</mi><mi>u</mi><mi>t</mi></mrow></msub></mrow></math></span> constantly decreases as χ increases from 0 to 1.0. In the tests with χ ≤ 0.6, <span><math><mrow><msub><mi>p</mi><mn>3</mn></msub></mrow></math></span> caused by acoustically enhanced combustion becomes the pressure peak with the highest amplitude in the internal pressure profile, but the pressure peak <span><math><mrow><msub><mi>p</mi><mn>2</mn></msub></mrow></math></span> induced by the external explosion dominates the internal pressure trace for χ > 0.6. In comparison to the H<sub>2</sub>/CH<sub>4</sub>/air deflagration experiments using an inertialess vent cover, the shape of the external fireball is quite similar for smaller χ in the current study with an inertial vent panel. However, the use of the inertial vent panel results in a more flattened external fireball for larger χ. The highest amplitude of the external pressure peak (<span><math><mrow><msub><mi>p</mi><mrow><mi>e</mi><mi>x</mi><mi>t</mi></mrow></msub></mrow></math></span>) and the maximum reduced overpressure (<span><math><mrow><msub><mi>p</mi><mrow><mi>r</mi><mi>e</mi><mi>d</mi></mrow></msub></mrow></math></span>) increase with increasing χ. Whether the studies are performed with inertial and inertialess vent covers or FLACS simulations, the formation time (Δt) of <span><math><mrow><msub><mi>p</mi><mrow><mi>e</mi><mi>x</mi><mi>t</mi></mrow></msub></mrow></math></span> decreases linearly with increasing χ, but <span><math><mrow><msub><mi>p</mi><mrow><mi>r</mi><mi>e</mi><mi>d</mi></mrow></msub></mrow></math></span> increases linearly with <span><math><mrow><msubsup><mi>S</mi><mi>l</mi><mn>2</mn></msubsup></mrow></math></span>. The explosion overpressure simulated by FLACS is relatively close to the experimental results, and in particular, the simulated <span><math><mrow><msub><mi>p</mi><mrow><mi>r</mi><mi>e</mi><mi>d</mi></mrow></msub></mrow></math></span> agrees very well w","PeriodicalId":16291,"journal":{"name":"Journal of Loss Prevention in The Process Industries","volume":"94 ","pages":"Article 105546"},"PeriodicalIF":3.6,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lithium-ion batteries usage is rapidly growing due to their superior performance compared to other battery chemistries. However, they involve the risk of thermal runaway, which can cause catastrophic accidents. A large number of studies investigated the behaviour of cells undergoing thermal runaway. In hazardous areas, lithium-ion batteries may be used under specific conditions, for example in flameproof enclosures. However, there are few studies on this topic, limiting the information on how flameproof enclosures must be designed to contain a thermal runaway event and mitigate the risk. Notified bodies conducting type tests of flameproof enclosures usually do not have the capability to work with lithium-ion batteries in thermal runaway. However, gas explosions are regularly employed to test the enclosure's ability to withstand pressure. In order to replace the lengthy destructive tests with batteries in the future, it is envisioned to reproduce the pressure load due to the thermal runaway of a battery on the flameproof enclosure by a gas explosion. This work is the first step towards this goal. To this end, the temporal pressure development inside a flameproof enclosure during a thermal runaway of 18650 lithium-ion cell is reproduced by gas explosions. The cell was heated to thermal runaway in an air-filled flameproof enclosure and the resulting pressure was measured as a function of time. Initially, preliminary tests of different cell chemistries identified NMC811 and LCO as giving the highest load on the flameproof enclosure employed in this study. Due to its better reproducibility, NMC811 was selected as the load to be reproduced. Various combustibles in air were then ignited in the same flameproof enclosure without the cell. The highest pressure and the pressure rise time were varied by the type of combustible and its concentration in air. The burnable gases used were hydrogen, methane, propane, ethylene and acetylene in different mixtures with air. The results show that the pressure evolution due to the thermal runaway of the NMC811 cells can be reproduced by gas explosions.
{"title":"Reproduction of the pressure load due to the thermal runaway in a flameproof enclosure by gas explosions","authors":"Inka Peschel , Stefanie Spörhase , Amiriman Kianfar, Detlev Markus, Stefan Essmann","doi":"10.1016/j.jlp.2024.105539","DOIUrl":"10.1016/j.jlp.2024.105539","url":null,"abstract":"<div><div>Lithium-ion batteries usage is rapidly growing due to their superior performance compared to other battery chemistries. However, they involve the risk of thermal runaway, which can cause catastrophic accidents. A large number of studies investigated the behaviour of cells undergoing thermal runaway. In hazardous areas, lithium-ion batteries may be used under specific conditions, for example in flameproof enclosures. However, there are few studies on this topic, limiting the information on how flameproof enclosures must be designed to contain a thermal runaway event and mitigate the risk. Notified bodies conducting type tests of flameproof enclosures usually do not have the capability to work with lithium-ion batteries in thermal runaway. However, gas explosions are regularly employed to test the enclosure's ability to withstand pressure. In order to replace the lengthy destructive tests with batteries in the future, it is envisioned to reproduce the pressure load due to the thermal runaway of a battery on the flameproof enclosure by a gas explosion. This work is the first step towards this goal. To this end, the temporal pressure development inside a flameproof enclosure during a thermal runaway of 18650 lithium-ion cell is reproduced by gas explosions. The cell was heated to thermal runaway in an air-filled flameproof enclosure and the resulting pressure was measured as a function of time. Initially, preliminary tests of different cell chemistries identified NMC811 and LCO as giving the highest load on the flameproof enclosure employed in this study. Due to its better reproducibility, NMC811 was selected as the load to be reproduced. Various combustibles in air were then ignited in the same flameproof enclosure without the cell. The highest pressure and the pressure rise time were varied by the type of combustible and its concentration in air. The burnable gases used were hydrogen, methane, propane, ethylene and acetylene in different mixtures with air. The results show that the pressure evolution due to the thermal runaway of the NMC811 cells can be reproduced by gas explosions.</div></div>","PeriodicalId":16291,"journal":{"name":"Journal of Loss Prevention in The Process Industries","volume":"94 ","pages":"Article 105539"},"PeriodicalIF":3.6,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-04DOI: 10.1016/j.jlp.2025.105544
Yinghui Liu , Qing Peng , Zhongze Fan , Yonghuang Zheng , Haifeng Wang , Dan Wu , Yueguang Wei , Xiaoming Liu
Risk assessment plays a crucial role in the arrangement design of storage vessels with flammable fuels or explosible chemicals. Underestimating the safety distance between vessels may lead to a domino catastrophe caused by scattered fragments from an unexpected explosion: an individual explosion resulting in a chain of explosions. In this work, we proposed a general mathematical model to study the fragment trajectory after explosion, with a focus on how the trajectory is affected by wind. Considering the wind effect in the proposed model, we predicted the fragment trajectory and probability distribution by solving the equations of motion for a projectile in the quadratic-resistant medium. Our results show that the maximum projection distance of the fragment varies linearly with the wind speed and increases nonlinearly with the explosion energy. Also, the derived probability distribution of scattering fragments aids in estimating safety distances between vessels with explosive fuel, providing a guideline for the risk assessment for vessel arrangement.
{"title":"Safety assessment of explosion fragment projection in a wind field","authors":"Yinghui Liu , Qing Peng , Zhongze Fan , Yonghuang Zheng , Haifeng Wang , Dan Wu , Yueguang Wei , Xiaoming Liu","doi":"10.1016/j.jlp.2025.105544","DOIUrl":"10.1016/j.jlp.2025.105544","url":null,"abstract":"<div><div>Risk assessment plays a crucial role in the arrangement design of storage vessels with flammable fuels or explosible chemicals. Underestimating the safety distance between vessels may lead to a domino catastrophe caused by scattered fragments from an unexpected explosion: an individual explosion resulting in a chain of explosions. In this work, we proposed a general mathematical model to study the fragment trajectory after explosion, with a focus on how the trajectory is affected by wind. Considering the wind effect in the proposed model, we predicted the fragment trajectory and probability distribution by solving the equations of motion for a projectile in the quadratic-resistant medium. Our results show that the maximum projection distance of the fragment varies linearly with the wind speed and increases nonlinearly with the explosion energy. Also, the derived probability distribution of scattering fragments aids in estimating safety distances between vessels with explosive fuel, providing a guideline for the risk assessment for vessel arrangement.</div></div>","PeriodicalId":16291,"journal":{"name":"Journal of Loss Prevention in The Process Industries","volume":"94 ","pages":"Article 105544"},"PeriodicalIF":3.6,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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