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The venting process is one of the most important events during the thermal runaway (TR) of lithium-ion batteries (LIBs) in determining fire accidents, while different ambient pressures will exert an influence on the venting events as well as the TR. Ternary nickel–cobalt–manganese (NCM) batteries with a 75% state of charge (SOC) were employed to conduct TR tests under different ambient pressures in a sealed chamber with dilute oxygen. It was found that elevated ambient pressure results in milder ejections in terms of jet temperature and mass loss. Gas venting characteristics were also obtained. Additionally, the amount of carbon dioxide (CO2), hydrogen (H2), methane (CH4), and ethylene (C2H4) released increase with ambient pressure, while carbon monoxide (CO) varies inversely with ambient pressure. The higher the ambient pressure is, the greater the flammability risk is. The molar amount of C, H, O, and total gases released shows a positive correlation with the maximum battery temperature and ambient pressure. This study will support the design of safety valves and help reveal the effects of venting events on the evolution of TR.

Stress damage in operational natural gas venting pipes is a complex issue that requires pipeline designs tailored to specific operational conditions. This study aims to accurately predict operational stress during the blow‐off process by leveraging design and operational parameters to assess potential pipeline damage. Five machine learning (ML) methods—gradient boosting regression (GBR), k‐nearest neighbor (KNN), deep neural network (DNN), support vector machine (SVM), and decision tree (DT)—were employed to predict stress damage within the gas transmission station’s blow‐off system. A dataset of 1200 entries was collected from finite element simulation calculations, with 90% allocated for training and 10% for testing. Notably, the GBR method outperformed the others, achieving an R 2 of 0.95, an RMSE of 4.87, and an MAE of 3.33.

Widespread gas venting along the Cascadia margin is investigated from acoustic water column data and reveals a nonuniform regional distribution of over 1100 mapped acoustic flares. The highest number of flares occurs on the shelf, and the highest flare density is seen around the nutrition-rich outflow of the Juan de Fuca Strait. We determine ∼430 flow-rates at ∼340 individual flare locations along the margin with instantaneous in situ values ranging from ∼6 mL min −1 to ∼18 L min −1 . Applying a tidal-modulation model, a depth-dependent methane density, and extrapolating these results across the margin using two normalization techniques yields a combined average in situ flow-rate of ∼88 × 10 6  kg y −1 . The average methane flux-rate for the Cascadia margin is thus estimated to ∼0.9 g y −1 m −2 . Combined uncertainties result in a range of these values between 4.5 and 1800% of the estimated mean values. Methane venting is a widespread phenomenon at the Cascadia margin, however a comprehensive database of methane vents at this margin is lacking. Here the authors show that the margin-wide average methane flow-rate ranges from ~4 × 10 6 to ~1590 × 10 6  kg y −1 and is on average around 88 ± 6 × 10 6  kg y −1 .

The article examines methods for protecting buildings against internal explosions through the implementation of safety rotary structures. The study analyzes various approaches to structural safeguarding during internal blast events, with particular focus on different types of safety structures and their operational parameters. The research investigates the determination of gas venting areas in buildings using rotary mechanisms designed to ensure occupant safety. Key parameters such as the sealing depth and flap thickness of safety structures are evaluated for their role in forming effective gas outflow zones. The work establishes a functional relationship between the dimensions of the safety structure flap and the resulting area for primary gas venting and pressure relief. Additionally, the study comprehensively considers the influence of safety structure embedment depth and material thickness on blast mitigation performance. These findings provide valuable insights for optimizing building safety systems in explosion-prone environments.

Gas escape from volcanic systems is regulated by permeable pathways. When gas escape is hindered, pressure within the edifice can increase, possibly resulting in explosive eruptions. We present a study on enclave bearing dome lavas from Chaos Crags and Lassen Peak, California, to understand the impact of mechanical and textural heterogeneities on the permeability fabric of dome lavas. We combine field and laboratory measurements of permeability and porosity. The data show that in the presence of mechanical heterogeneities, shear deformation induces permeability anisotropy and heterogeneity with higher permeability parallel to the shear fabric and varying on decimeter scale around mechanical heterogeneities. Based on these insights we discuss implications for the accumulation of gas pockets in the conduit margin, which may contribute to cyclic explosive gas venting commonly observed at dome forming volcanoes.

This study employs a validated dynamic multiphase flow model to quantify the severe operational impacts of impaired annulus gas venting on Electrical Submersible Pump (ESP) performance. Utilizing high-frequency field data from a documented gas-lock incident—initiated by the inadvertent closure of a valve—the analysis demonstrates how a surge in the pump intake gas flow rate (from 0.2 to 0.4 MMSCFD) triggers a cascade of system failures. These include a severe oscillatory decline in the liquid flow rate of up to 300 STBD, leading to an overall production loss of 23%. The incident further induced significant system instability, manifested as amperage fluctuations between 40 and 58 A, Pump Intake Pressure (PIP) oscillations with an amplitude of ± 30 psi, and impaired motor cooling. The primary contribution of this work is a detailed causal analysis and dynamic quantification of the gas-lock progression, establishing a benchmark for its severity. These findings underscore the critical, non-negotiable requirement for proper annulus venting in both ESP design and operational procedures to prevent catastrophic production losses and equipment damage.

Methane is a greenhouse gas and identified as a key driver of near-term climate change. Bottom-up approaches estimate annual methane loss from US natural gas production and transport at 6 Tg, but recent studies suggest this may be an underestimate. To investigate this possibility, an equipment-based emissions inventory, using EPA emission factors, was developed to calculate methane emissions from oil and gas operations in the Delaware basin, USA. Emission factors and activity data were then updated using contemporary and region-specific measurement data. The original inventory estimated emissions at 315 Gg CH4 y−1 (gas production-normalized rate of 0.6% loss), while the updated inventory estimated emissions of 1500 Gg CH4 y−1 (2.8% loss). The largest changes resulted from large fugitive emissions from oil production (+430 Gg CH4 y−1), updating maintenance activity emissions (+214 Gg CH4 y−1), considering flaring inefficiency (+174 Gg CH4 y−1), and the inclusion of associated gas venting (+136 Gg CH4 y−1). This study suggests that a systematic underestimate probably exists in current bottom-up inventories and identifies sources currently missing or may be incorrect. We also strongly recommend that emission factors should be validated through direct comparison against measurement campaigns that include long-tail distributions typical of oil and gas activities.

The active emission of gas (mainly methane) from terrestrial and subsea permafrost in the Russian Arctic has been confirmed by ample evidence. In this paper, a generalization and some systematization of gas manifestations recorded in the Russian Arctic is carried out. The published data on most typical gas emission cases have been summarized in a table and illustrated by a map. The tabulated data include location, signatures, and possible sources of each gas show, with respective references. All events of onshore and shelf gas release are divided into natural and man-caused. and the natural ones are further classified as venting from lakes or explosive emissions in dryland conditions that produce craters on the surface. Among natural gas shows on land, special attention is paid to the emission of natural gas from Arctic lakes, as well as gas emissions with craters formation. In addition, a description of the observed man-caused gas manifestations associated with the drilling of geotechnical and production wells in the Arctic region is given. The reported evidence demonstrates the effect of permafrost degradation on gas release, especially in oil and gas fields.

With the rapid development of lithium-ion battery technology, powertrain electrification has been widely applied in vehicles. However, if thermal runaway occurs in a lithium-ion battery pack, the venting gas in the cells will spread and burn rapidly, which poses a great threat to safety. In this study, a 2D CFD simulation of the combustion characteristics of cell venting gas in a lithium-ion battery pack is performed, and the possibility of detonation of the battery pack is explored. First, a numerical model for the premixed combustion of venting gas is established using a two-step combustion mechanism. The combustion characteristics are then simulated in a 2D channel for the stoichiometric combustible mixture, and the variations in the flame velocity and pressure increment in the flow channel are analyzed. Next, the effects of the initial conditions inside the battery pack, including the pressure, temperature, and excess air coefficient, on the flame propagation process and pressure variation are evaluated. The results indicate that the flame velocity increases with the increase in the initial pressure or temperature and that the influence of the initial temperature is more acute. The maximum flame speed is achieved with a slightly rich mixture, about 450 mm·s−1. When the excess air coefficient is around 0.9, the flame propagation changes from a slow deflagration to a fast deflagration, which causes a high risk of explosion for the battery pack.

For cold venting processes frequently employed in oil and gas fields, precisely predicting the instantaneous diffusion process of the vented explosive and/or toxic gases is of great importance, which cannot be captured by the Reynolds-averaged Navier–Stokes (RANS) method. In this paper, the large eddy simulation (LES) method is introduced for gas diffusion in an open space, and the diffusion characteristics of the sulfur-containing natural gas in the cold venting process is analyzed numerically. Firstly, a LES solution procedure of compressible gas diffusion is proposed based on the ANSYS Fluent 2022, and the numerical solution is verified using benchmark experiments. Subsequently, a computational model of the sulfur-containing natural gas diffusion process under the influence of a wind field is established, and the effects of wind speed, sulfur content, the venting rate and a downstream obstacle on the natural gas diffusion process are analyzed in detail. The results show that the proposed LES with the DSM sub-grid model is able to capture the transient diffusion process of heavy and light gases released in turbulent wind flow; the ratio between the venting rate and wind speed has a decisive influence on the gas diffusion process: a large venting rate increases the vertical diffusion distance and makes the gas cloud fluctuate more, while a large wind speed decreases the vertical width and stabilizes the gas cloud; for an obstacle located closely downstream, the venting pipe makes the vented gas gather on the windward side and move toward the ground, increasing the risk of ignition and poisoning near the ground. The LES solution procedure provides a more powerful tool for simulating the cold venting process of natural gas, and the results obtained could provide a theoretical basis for the safety evaluation and process optimization of sulfur-containing natural gas venting.