Journal of Loss Prevention in The Process Industries最新文献

If a fire occurs in an area with multiple installations storing or handling flammable materials, it may escalate from one installation to another to form so-called domino effects. The propagation of fire-induced domino effects has temporal properties due to the heating effect of the thermal radiation of fires. Under the action of thermal radiation, the surrounding installations may be damaged, and the probability of damage can be estimated by Probit models. As a result, the propagation path exhibits characteristics of randomness. As new installations catch fire due to domino effects, the thermal radiation received by a target installation changes, so that the damage probability changes dynamically throughout the accident process. This study aims at further improve the previous study of the matrix modeling approach for fire-induced domino effects by considering the heating process of facilities under fire accidents. The analysis process incorporating the damage probability calculation algorithm is presented. The improved approach is illustrated by the study of two cases.

To reduce the hazard of gas explosions, the weakening and inhibiting effects of additional cavities and obstacle deflectors on the propagation of gas explosions in straight pipes were investigated by means of comparative experiments in a self-constructed experimental platform. The results show that an additional cavity in the straight pipe can reduce the intensity of the gas explosion. Moreover, the obstacle deflector in front of the cavity can further weaken the intensity of the gas explosion. When the obstacle was located 0 m and 0.1 m in front of the cavity, the explosion flame and shockwave were deflected to hit the inner wall of the cavity, then rebounded, and sufficiently diluted by the air in cavity, thus the subsequent development of the explosion was restricted. The second peak overpressure was reduced by 5.15% and 27.82%, respectively, compared to that of the pipe only with a cavity, and the explosion flame was diverted and quenched in the cavity. When the obstacle was located 0.2 m in front of the cavity, the intensity of the gas explosion increased, and the flame quickly crossed through the cavity and rushed out of the pipe end. An obstacle in the middle of the vertical direction is more effective at reducing the strength of the gas explosion than an obstacle located at the bottom. The minimum amount of ABC dry powder (containing 75% ammonium dihydrogen phosphate and 15% ammonium sulfate) needed to prevent gas explosions is reduced by the additional cavity in the straight pipe. When the obstacle is located in front of the cavity, the minimum amount of ABC dry powder available for explosion prevention is further reduced. The reduction in the amount of ABC dry powder required for explosion prevention also intuitively reflects the weakening effect of the cavity and obstacle deflector on the gas explosion.

The layout of chemical plants is a significant step to promote the safe and efficient operation of a chemical factory. In the actual production process, the chemical process plant layout may be affected by immovable hazards outside the available layout area. In this paper, the external hazard unit is arranged as one of the chemical process plants. The domino effect potential of all chemical process plants is quantified by using the classical domino hazard index (DHI). A layout optimization model considering the effects of external hazard units has been proposed to obtain the optimal plant layout from economic and safety aspects. The feasible layout solutions are obtained under the orientation, boundary and non-overlapping constraints by the non-dominated sorting genetic algorithm II (NSGA-Ⅱ). The proposed model is further analyzed through a hypothetical case of three storage tanks outside the acrylic acid (AA) production plant layout area. The results show that the total cost range for the optimal solution is 650348–1365443 $, with corresponding DHI values ranging from 29 to 129. The plant with larger DHI value will be arranged to far away from the external hazard units to obtain a safer layout. This work can provide rational layout solutions for the layout designers to make different decisions according to the actual situation.

In the context of the process industry safety, one of the main accidental scenarios is the release of high-pressure gaseous material. Since natural gas is highly flammable, the likelihood of ignition increases as the jet develops, with a maximum area of effect related to its lower flammability limit (LFL). This work aims at simulating and evaluating the interaction between high-pressure natural gas jets and cuboid obstacles, which were selected due to their prevalence in the process industry as storage units or buildings present in industrial parks. The maximum extent of the cloud at the LFL of natural gas is often influenced by the jet-obstacle interactions, necessitating complex numerical methods like computational fluid dynamics (CFD) for accurate estimation. Therefore, this study provides pivotal insights that challenge traditional modelling approaches, like integral ones, offering cost-effective alternatives where needed without compromising on safety.

The findings indicate that using a CFD approach is not always necessary, as it largely depends on the storage pressure, diameter size, and the release height of the jet. At storage pressures of 65–130 bar with an orifice diameter of 2.54 cm, and a release height above 2.75 m, simpler methods like integral models are applicable without any substantial reliability loss. This is especially true when the cuboid obstacle is farther away from the release source. At lower release heights, especially if coupled with a larger orifice diameter, the CFD approach should be utilised as jet-cuboid interactions become highly relevant to the development of the jet.

The occurrence of accidents is often influenced by many factors, which result in the complexity of the causes of accidents. Therefore, clarifying the accident chain of the explosion accident is of great significance for the daily management of safety. In this study, a novel method of the core accident chain based on the traditional fuzzy-DEMATEL-ISM method was proposed. This method can clarify the importance of each accident chain and rank them accordingly by calculating their weighted centralities. Then, the explosion accident caused by the contact of molten aluminium and water, which has caused heavy casualties and property losses, is analyzed systematically. In order to clarify the impact relationships and hierarchical structure of the various factors in the complex explosion accident systems, and establish the accident system models, twenty-two factors were summarized, and the evolution process of explosion accident were obtained by the fuzzy-DEMATEL-ISM approach. The results reveal that equipment damage or failure has the most direct impact to the explosion accidents. The core accident chain that national policy (aluminium market demand)→incomplete safety management system→disordered on-site management→insufficient lighting→physical discomfort→improper operation→equipment damage or failure is obtained, which has the most significant influence on the occurrence of explosion accidents. The result analysis is employed to give some advice. This research is helpful for safety practitioners to develop accident prevention strategies and make aluminum production safer.

In order to study the effect of ethane on gas explosions, the macroscopic properties, thermodynamics and kinetics of gas explosions were investigated using Chemkin numerical simulation software with the GRI-Mech 3.0 mechanism. Ethane was added to methane-air mixtures at seven different concentrations, such as 0%, 0.1%, 0.3% and so on, at constant initial temperature (1200 K) and pressure(0.9atm), respectively. The results show that the maximum explosion pressure, explosive power and ·H content was all maximized when the volume fraction of ethane was 3%, which was the most effective volume addition to promote gas explosion. Ethane reduced the time to peak energy of key radical reactions from 0.049s to 0.003s and reduced the sensitivity factors for reactions such as R155 and R158. When the added ethane was 8%, R158 and R98 shifted from inhibiting methane consumption to promoting methane consumption. Calculated by Arrhenius and Lindemann formulae found that ethane can act as the third molecule in unimolecular reactions, increasing the reaction rate constant and decreasing the activation energy, so accelerating the reaction. Due to the low addition of ethane, there was still a large amount of N₂ acting as the third molecule, so the decrease in activation energy was small.

Recently, considerable attention has been paid to blending hydrogen with natural gas transmission pipelines. However, risk assessments using different hydrogen blend concentrations in natural gas pipelines have not been thoroughly investigated. Thus, the main objective of this study is to carry out a quantitative risk assessment of hydrogen blending into the transmission of natural gas. For this, six different concentrations of hydrogen blending, three pipes and four different release holes are used in this study. The effect distance decreased with increasing hydrogen concentration for the jet fire case. For case of vapor cloud explosions, the downwind distance of the maximum explosion overpressure increased with increasing hydrogen concentration. It was also found that as the hydrogen concentration increased, the individual risk was sensitive to adjacent to the pipelines, however, it was less for far-fields. This study is expected to contribute to the safety measures for business sites with hydrogen blending into natural gas pipelines.

After drying, water-immersed coal is more prone to spontaneous combustion than raw coal. However, the influence mechanisms of particle size and water immersion duration on the physicochemical properties of coal dust, as well as the explosion and fire hazards of water-immersed coal dust, have not been sufficiently investigated. In this study, two particle sizes of coal dust were selected, and experiments were conducted using the Godbert-Greenwald furnace, Hartmann tube, Muffle furnace, and Fourier Transform Infrared Spectrometer. The study investigated the impact of different water immersion times, dust particle sizes, and dust concentrations on the sensitivity of coal dust fires and explosions, analyzed the process of functional group changes in coal dust particles in water and other mechanisms of transformation. The results indicated that the water immersion process increased the number of active functional groups on the surface of coal dust, significantly reducing the Minimum Ignition Temperature (MIT) and Minimum Ignition Energy (MIE) values for different samples, and also enhancing the ignition sensitivity and peak temperature of coal dust layer fires. This study contributes to a deeper understanding of the characteristics of coal dust and is of great significance for improving the prevention and control of coal dust fires and explosions.

In deep mine production operations, the challenging operating environment intensifies the workload and pressure on coal miners. Long-term exposure to high-intensity operating pressure can seriously impact the physical and mental health of miners, leading to unsafe behaviors and accidents. To identify the pressure of miners' operations, this paper examines various driving scenarios, such as the deep-well tunneling machine cutting the wall and opening the alley, the shoveling machine shoveling ore, and the pickup truck driver transporting. The paper randomly collects facial images of miners during each operation using an explosion-proof CCD camera to obtain the facial expression characteristic data of miners. The Ferface2013 facial expression dataset was used to establish the dataset. The depth separable convolutional neural network MiniXception was used for training and to output the classification results of the pressure degree of deep shaft miners. A MiniXception-based miners' operating pressure recognition model was established. The training time, precision, recall, F1 score, and classification accuracy confusion matrix were selected. The study evaluated the effectiveness of the recognition model by measuring its training time, precision, recall, F1 score, and classification accuracy confusion matrix. The results indicate that the model has a correct recognition rate of 88% for the pressure state, 91% for the pleasure state, and 74% for the normal state. The overall accuracy of the model is 0.843. Therefore, the MiniXception recognition model is suitable for recognizing the pressure of miners' operations in deep mines. This can meet practical needs and is useful for preventing major accidents in mines, managing on-site safety, and managing safety in non-hazardous areas. It has important theoretical and practical significance.

Sodium percarbonate (SPC), also known as sodium carbonate–hydrogen peroxide, is a bleaching. The thermal decomposition of SPC produces oxygen, which slightly increases its bleaching ability. Nevertheless, the heat and oxygen produced pose a fire risk, potentially leading to spontaneous combustion when the SPC is stored alongside flammable materials. Previous studies have noted that water vapour affects SPC decomposition; However, the moisture absorption of SPC and the particular details of the effect have not been reported. In this study, the moisture absorption test revealed the deliquescence of SPC above 75% relative humidity (RH) and its hygroscopicity above 60% RH. Deliquescence occurred at 30 °C and 84% RH for 192 h, and the absorbed water caused its decomposition. Adiabatic calorimetry revealed only 30 wt% water, which was similar to that absorbed by SPC stored for 24 h at 30 °C and 97% RH, decreasing the thermal stability of SPC. These results indicate that the humidity surrounding the SPC is an extremely important parameter for estimating thermal hazards during the storage and manufacturing of SPC.