Abstract
Vapor cloud explosion (VCE) accidents in recent years such as the Buncefield accident in 2005 indicate that VCEs in process plants may lead to unpredicted overpressures, resulting in catastrophic disasters. Although a lot of attempts have been done to assess VCEs in process plants, little attention has been paid to the spatial-temporal evolution of VCEs. This study, therefore, aims to develop a dynamic methodology based on discrete dynamic event tree to assess the likelihood of VCEs and the vulnerability of installations. The developed methodology consists of six steps: (i) identification of hazardous installations and potential loss of containment (LOC), (ii) analysis of vapor cloud dispersion, (iii) identification and characterization of ignition sources, (iv) explosion frequency and delayed time assessment using the dynamic event tree, (v) overpressure calculation by the Multi-Energy method and (vi) damage assessment based on probit models. This methodology considers the time dependencies in vapor cloud dispersion and in the uncertainty of delayed ignitions. Application of the methodology to a case study shows that the methodology can reflect the characteristics of large VCEs and avoid underestimating the consequences. Besides, this study indicates that ignition control may be regarded as a delay measure, effective emergency actions are needed for preventing VCEs.
Highlights
In petroleum and chemical industrial plants, fire, explosion and toxic release arising from loss of containment (LOC) are concerned as major hazards [1,2,3]
The present study aims to establish a dynamic risk assessment methodology based on a discrete dynamic event tree (DDET) to in tegrate plant physical models and ignition sources into a stochastic si mulation engine so as to model the timing dependencies and ignition uncertainty in the evolution of Vapor cloud explosion (VCE)
This study introduced a new methodology based on dynamic event tree (DET) to model the vulnerability of process plants to VCEs, con sidering both the spatial-temporal dispersion of vapor cloud and the uncertainty of delayed ignition time (DIT)
Summary
In petroleum and chemical industrial plants, fire, explosion and toxic release arising from loss of containment (LOC) are concerned as major hazards [1,2,3]. With respect to the amount and rate of vaporization, large releases often result in vapor cloud explosion (VCE) rather than fires [5]. Abdolhamidzadeh et al [6] investigated 224 domino accidents that occurred in the process in dustries and indicated that explosion is the most frequent cause of domino effects (57%). Several catastrophic accidents occurred in recent years due to VCEs, such as the Puerto Rico explosion (2009, USA), the Sitapura explosion (2009, India), and the Amuay explosion (Venezuela, 2012). The Amuay disaster caused by a large VCE at the Amuay refinery, situated in northwestern Venezuela, led to over 50 fatalities and more than 100 injures, damaging 1600 houses and re sulted in financial losses up to $1 billion [7,8]
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