Search

The number of pressure vessel bursts (PVBs) has reduced since the 1990s due to the introduction of many rules and regulations. However, accidents frequently occur during pressure resistance tests (pneumatics) and there are scant safety guidelines for examining pressure vessels. Thus, this study proposes a safe distance to prevent accidents during a test, based on the explosion energy and vessel shape. First, the maximum explosion energy was computed using Brode's equation and the distance and overpressure were nondimensionalized via Sachs' scaling. Next, the overpressure ratio of the spherical tank (opsphere) was calculated based on the overpressure ratio of the cylindrical tank (opcylinder), considering the length to diameter ratio of the cylindrical vessel. Finally, the function of the safety distance was obtained. The result was validated by comparing it with data from the catastrophic failure that occurred at D. D. Williamson & Co. Inc. in 2003. This study could help establish safety guidelines and the prevention of PVB damage. [ABSTRACT FROM AUTHOR]

Liquefied natural gas (LNG) floating production storage offloading, or floating liquefied natural gas (FLNG), is an offshore unit used to produce LNG from offshore gas reservoirs. The liquefaction is critical process for liquefying natural gas (NG) into LNG. Among NG liquefaction technologies used in the industry, single mixed refrigerant, dual mixed refrigerant (DMR), and the nitrogen expansion liquefaction process have been considered for FLNG on account of its space limitations and higher safety standards. In particular, the DMR liquefaction process is preferred for a large FLNG because of its high efficiency. Many studies have been suggested about an efficiency of DMR, but a few studies have been conducted on their process safety although different configurations in process concepts can cause meaningful differences in operating conditions and safety. In this study, two DMR process configurations were optimized to maximize the efficiency and conceptual explosion risk was analyzed to compare their risk at the conceptual design stage. The results showed a difference between the explosion risks by the differences in the optimal mixed refrigerant compositions and number of devices, with similar efficiencies. These results can provide insight for a risk management strategy at the conceptual design stage, to minimize the unexpected cost generation. © 2018 American Institute of Chemical Engineers Process Process Saf Prog 38: 87–98, 2019 [ABSTRACT FROM AUTHOR]

This paper describes and reports an analysis of an explosion accident at a wastewater storage pond in South Korea, which resulted in six fatalities and one injury. This study was aimed at analyzing and determining the possibility of fracture of concrete structure by vapor cloud explosion (VCE) and ignition point of explosion, using computational fluid dynamics (CFD) for the explosion simulation. The result obtained via CFD analysis was connected with finite element analysis (FEA) to accurately review the structural damages resulting from the explosion. As a result, the mechanism of the accident was determined, and preventive solutions against such accidents are recommended. This study was aimed at analyzing and determining the possibility of fracture of concrete structure by vapor cloud explosion (VCE) and ignition point of explosion, using computational fluid dynamics (CFD) for the explosion simulation. [ABSTRACT FROM AUTHOR]

Due to numerous hazardous chemicals to handle, the process plant industry has a higher risk of fire, explosion, and toxic release than other industries. Reviewing the accidents at process plants in the past, it is clear that fire accidents occur with the highest frequency, leading this study to consider accidental fire scenarios at process plants. For the scenario of an incident, a jet fire involving a massive amount of hydrogen gas to be processed or delivered at the process plant has been selected. The analysis of incident outcome resulting from the hydrogen jet fire has been implemented through the computational fluid dynamics simulation methodology Kameleon FireEx. Based on the outcome of this simulation, the consequences of a jet fire with high temperature and heat radiation are analyzed and evaluated. In addition, the results from Phast ver. 7.11 simulation for the same scenario are presented for comparison and further validation. [ABSTRACT FROM AUTHOR]

The primary purpose of a flare model is to provide a reasonably accurate prediction of radiant heat flux at any point of interest around the flame in order to be able to define safe release locations. In order to do this, a flare model needs to provide a good prediction of the following critical flame parameters: flame length, flame tilt, and radiant heat fraction, including the impact of wind and release orientation on these parameters. In addition, the model needs to distribute the radiant heat along the flame in a reasonably realistic way and to allow for the transmissivity of the ambient air. Industry standard models for vertical flares include Chamberlain [Chamberlain, Chem Eng Res Des 65 (1987)], API 521 [API STANDARD 521, Pressure-Relieving and Depressuring Systems, 6th Edition, American Petroleum Institute, Washington DC, 2014], and Brzustowski & Sommer [API STANDARD 521, Pressure-Relieving and Depressuring Systems, 6th Edition, American Petroleum Institute, Washington DC, 2014]. These models were originally developed primarily based on hydrocarbon data. Several commercially available consequence models allow the use of these models for all flammable materials. Due to the lack of other options, these commercially available consequence software models are often applied to hydrogen, syngas (hydrogen/carbon monoxide mixtures), and other materials that are well outside the intended scope of the models. A review has been performed to evaluate applicability of the Chamberlain, API 521, and Brzustowski & Sommer models to hydrogen and syngas, including comparison with limited published data. As a result of this review, a number of significant concerns have been identified. This has led to initiation of a new test program to collect data specifically for hydrogen and syngas and the subsequent development of new models. © 2014 American Institute of Chemical Engineers Process Saf Prog 34: 141-146, 2015 [ABSTRACT FROM AUTHOR]

Hydrogen is a critical component in the production of cleaner fuels. Underground pipelines provide a safe, reliable supply of hydrogen to refineries and the petroleum industry. Proper assessment of the risks associated with underground hydrogen pipelines requires an accurate model of the jet fire consequence. This article will describe experimental and modeling work undertaken in order to define the appropriate methodology for utilizing DNV's PHAST software tool to represent the hydrogen jet fire from the rupture of underground hydrogen pipelines. Two experiments were conducted to measure the flow and radiation from an intentionally ignited rupture of a 6 in. diameter, 60 barg hydrogen pipeline buried 1 m underground. Adjustments to PHAST modeling parameters were required in order to obtain agreement between the measured and predicted radiation and flame length values. The modeling assumptions and parameter adjustments include: Velocity modification to account for interaction of the flow out of the two ends of the ruptured pipe and to model the subsequent discharge from the crater., Specification of the fraction of heat radiated., Specification of the angle of the release., © 2013 American Institute of Chemical Engineers Process Saf Prog, 2013 [ABSTRACT FROM AUTHOR]