查看更多>>摘要：In this study, "attenuation" and "substitution" strategies were applied to improve the inherent safety designs of exothermic reaction processes. The two strategies were implemented in the exothermic process of the esterification of methanol with acetic anhydride. Process simulation technology was used to compare the two strategies, and the process with moderate increases in temperature-pressure curves was identified. Large quantities of thermally inert and high-boiling-point reactants can be added to a reaction system to dilute the system. Thus, "attenuation" can reduce the values of process parameters such as temperature and pressure. The flammability, explosiveness, toxicity, and thermal inertness of the reaction system were examined for investigating the inherent safety characteristics of the solvent. Selecting a high-safety solvent considerably improves the inherent safety of processes. Transforming the strongly exothermic batch reaction process into a semibatch production process or a continuous production process reduces the severity of thermal runaway and improves process controllability. Thus, "substitution" of a process that has low inherent safety with a process that has high safety was realized.
查看更多>>摘要：In the Oil & Gas sector, the use of flammable substances stored and transported in gaseous form and under pressure conditions is quite common. In the field of industrial safety, high-pressure gaseous releases of a flammable material impacting an obstacle are of paramount importance, as possible accidental scenarios, due to their catastrophic consequences. Although hot release (i.e., jet fire scenarios) is a topic that has been largely covered in literature, cold releases (i.e., unignited flammable releases) did not. This gap increases when considering highpressure cold releases interacting with an obstacle. Being a probable situation when an accidental high-pressure loss of containment occurs, the need of reliable as well as quick tools for prompt safety evaluations of the hazardous area of this kind of scenario is of primary importance. To this aim, the present work proposes such a consequences assessment tool derived from an extensive CFD analysis of several possible situations of a cylindrical obstacle impinged by an unignited high-pressure gaseous methane jet.
查看更多>>摘要：Multi-hazard accidents in process industries, which can cause more severe consequences compared to individual accidents, have gained growing attention from administrators and scholars in recent years. With the development of process industries and the expansion of the urban area, high-risk zones may emerge in densely populated areas. Accurate risk assessment of the multi-hazard accidents in process industries is essential for protecting properties, human life, and the environment. This study reviews past studies on the risk assessment of three types of multi-hazard accidents in process industries: Natech events, domino effects, and concurrent hazards. The development trends of risk assessment of multi-hazard accidents are analyzed and the research gasps of past research are identified. Based on the identified gaps in previous research, future perspectives on multi-hazard research in process industries are discussed. To improve the assessment methods for multi-hazard risks, more advanced basic models and applicative risk analysis methods are required. Considering multi-hazard interactions and other factors are also important for process plants against multi hazards. This study can potentially contribute to developing better risk assessment models of multi-hazard accidents and therefore safer and resilient process industries.
Ejeh, Jude O.Liu, SongsongPapageorgiou, Lazaros G.
13页
查看更多>>摘要：In this work, we propose a multi-objective mixed-integer linear programming (MILP) model for evaluation of safe multi-floor process plant layout using the Dow's Fire & Explosion Index (F&EI). Two objectives are considered, namely the total monetary cost and the financial risk, and solved via the -constraint method. The total monetary cost consisted of the piping costs, horizontal and vertical pumping costs, land purchase cost, fixed and area-dependent floor construction cost, and the cost of protection devices. The financial risk was evaluated as the maximum probable property damage cost obtained using the F&EI evaluation procedure. The proposed model was applied to an ethylene oxide plant consisting of 7 equipment items with Pareto-optimal solutions showing that the financial risk can be greatly reduced by layout reconfiguration without the need for protection devices and their associated monetary costs. Further increase in the safety levels of the plant can then be achieved through protection device installation at a cost. These, and more information obtained, which are non-existent in previous single objective considerations, are helpful for a more informed decision making process in the planning stages of the design of chemical process plants.
Briggs, BrianFriedland, Carol J.Nahmens, IsabelinaBerryman, Charles...
10页
查看更多>>摘要：There are always significant challenges in improving the safety culture by changing and adding additional safety protocols. The unknown impacts of COVID-19 and how it quickly spreads led the industry to institute essential safety protocols. This paper addresses two problem statements. The first problem statement is: what are the additional safety protocols for process safety, construction & maintenance, and personal protective equipment requirements? The second problem statement is: what are the cost and schedule impacts of industrial construction projects resulting from implementing safety protocols and process safety during construction with the added PPE? While complying with added safety protocols, the industrial construction industry cannot forget that it has a distinct reputation for high incident rates and less than desirable safety performance. In 2017, the construction industry suffered 971 fatalities. This alarming number is compared to 1123 total fatalities in 2017 for the Gulf Coast States. The objective is to share the rationale and practices of social distancing, required additional PPE, and personal hygiene practices to reduce spreading and outbreaks during a pandemic within an industrial construction environment. Before any construction work, the process safety teams must clear, isolate, and tag out process lines, equipment, and instruments to be repaired or replaced. The information presented demonstrates the significant cost and schedule impacts that industrial construction companies will encounter during a pandemic like COVID-19. This paper aims to improve safety processes, cost & schedule impacts, and prescribe additional personal protective equipment in industrial construction during a pandemic such as COVID-19. The COVID-19 pandemic spread globally in a very short period. The reactions in mitigating the spread were suggestive, with little to no data on safety protective equipment and practices. The contribution this paper addresses are how to employ efficient safety practices and policies during a pandemic in an industrial construction environment.
Vinh-Tan NguyenRaghavan, Venugopalan S. G.Quek, Raymond Y. L.How, Lim Boon...
16页
查看更多>>摘要：The impacts of uncertainty in wind conditions on the spread of hazardous plume resulting from a jet leak during a Liquefied Natural Gas (LNG) bunkering operation were investigated. Computational Fluid Dynamics (CFD) using the Reynolds-Averaged Navier Stokes (RANS) solver with multi-species transport and a transient leak model for keyhole leak was used for the simulation of a simplified bunkering station. Following detailed validation & verification, the sensitivity of the safety zone extents to the wind conditions was demonstrated. CFD results reinforced the strong dependence of the maximum spread distance on wind conditions and enclosure geometry. To quantify the impact of input uncertainty from wind conditions on the plume spread, a reduced-order model (ROM) was developed using the proper orthogonal decomposition (POD) of CFD results on sampled conditions. ROM-POD enables a fast evaluation of the plume under changing wind conditions and acts as an efficient forward model for uncertainty quantification using Polynomial Chaos Expansion (PCE) technique. The spatial distribution of plume residence time under the same input uncertainty was also obtained from the proposed approach showing its potential in risk assessment and design of bunkering facilities.
查看更多>>摘要：Statistics on accidents in confined spaces reveal that many workers are injured and killed each year while working in confined spaces. The main cause of accidents and fatalities due to work in confined spaces is related to the lack of awareness about the presence and the risks of such unconventional workplaces. A confined space hazard assessment and risk control program should be implemented prior to access a confined space, aiming to control the risks associated with working in a confined space. This paper introduces a structured procedure and a digital tool for mobile devices, which aim to increase workers' awareness about the risks of working in confined spaces. The proposed tool investigates four different categories of confinement that characterize confined spaces: geometry, access, internal configuration, and atmosphere. After completing the procedure on the mobile application, the user, e.g. the employer or the company's safety professional, receives a list of potential issues that should be addressed before entering the space. Three case studies show the application of the proposed methodology to three suspected confined spaces.
查看更多>>摘要：In order to reveal the deflagration characteristics and evolution law of LPG (liquefied petroleum gas)/DME (dimethyl ether) blended gas cloud under normal temperature and pressure in open space under different equivalence ratios and DME contents (0%?30%?50%?70%?100%), experiments and numerical simulations were conducted to study the deflagration overpressure, flame speed, gas velocity and their interactions, and the sensitivity analysis of key elementary reactions of LPG/DME blended gas was carried out. The results showed that the addition of DME can elevate the deflagration intensity of LPG, and in the same equivalent ratio the more of DME was blended into LPG, the greater the peak overpressure was, and so as to the maximum flame speed and the peak gas velocity. What's more, within certain limits the peak overpressure generated by gas deflagration showed a linear increase with the increase of the maximum flame speed. During the gas cloud deflagration, the flame speed went through three stages, including flame formation, acceleration and attenuation, and the DME blended ratio (lambda) showed significant effect on the flame acceleration process. Then, the formation mechanism of overpressure and the state field distribution during gas cloud deflagration were proposed. The chemical reaction rate has a decisive effect on the flame speed, and the maximum flame speed restricts the peak overpressure and the peak gas velocity. Finally, the effect of promoting reaction is dominant after the addition of DME according to the sensitivity analysis.
查看更多>>摘要：Evacuation route optimization plays an important role in safe evacuation for toxic leakage accidents. We propose an approach for route optimization under real-time toxic gas dispersion by combining computational fluid dynamics (CFD) code and the Dijkstra algorithm. CFD code is used to simulate the toxic gas dispersion to predict the spatial-temporal distribution of concentrations, which is related to the calculation of the inhaled dose. Taking the dose as the weights of arcs, the concentrations predicted by CFD are embedded into the modified Dijkstra algorithm to calculate the optimal route with minimal total inhaled dose. The results show that the time before evacuation affects the evacuation route optimization, and the death probability exhibits an "S"-shaped growth as time increases. The optimal route may vary with wind direction dominating the direction of toxic gas dispersion because of the change of weights of arcs. Workers wearing protective equipment are allowed to pass through areas with high-concentration toxic gas, and the length of the optimal evacuation route decreases with the level of safety protection. The proposed methodology with appropriate modification is suitable for evacuation route optimization in fires.
查看更多>>摘要：There have been many advancements and developments in hazard and risk analysis techniques over the past several decades. Since then, many researchers integrated various dynamic aspects into the conventional static analysis of hazard and risk associated with various failure cases and accidents. Dynamic Risk Analysis is an advanced continuous real-time approach that deals with rapidly changing circumstances to update and integrate the changing risk levels into overall risk profile. The emergence of various dynamic frameworks and methodologies is a solution against the restrictions on conventional static hazard identification and risk estimation techniques. DRA may be applied throughout the lifetime of a dynamic system or process starting from its design stage ensuring safe operations, easy maintenance and test activities. It can also support a real-time risk-informed decision-making and risk management. Despite its advantages, the dynamic approaches may possess many challenges and limitations necessitating a comprehensive literature review on the evolution of various DRA techniques. A better understanding of the current trend of dynamic methodologies is also necessary to explore the scope of application of more advanced hybrid dynamic methodologies for an effective real-time health, safety and environment management.
NSTL
Elsevier