Pressurisation of fixed roof storage tanks due to external fires
Abstract
This study deals with one of the phenomena which is able to generate fire balls like the one which was observed during the 1987 Edouard Herriot port of Lyon fire. Reflections led on this accident have pushed to consider the phenomenon of tank pressurization as a potential initiating event of the fire ball observed. In concrete terms, when a fixed roof storage tank is surrounded by a pool fire, and when the vents or the insulation are not correctly designed, the inside pressure can raise until the mechanical limits of the structure are reached. The aim of this study is to develop a tool which will allow to follow the variations of the pressure and temperature in the gas phase, highlighting if a pressure increase is possible or not. This will help the sizing of new tank vents and insulation of the walls, or evaluating the risk of already build structures, by solving the question occurrence of the accident, regarding the estimated external fire duration. The model also gives the temperature distribution in the liquid phase, at each time step. In case of rupture, this information will be useful to describe the phenomenological aspect of the accident after the rupture of the tank. It means that qualifying and quantifying the fire ball generated and its effect on persons and structures will be possible. Currently, although a few analytical models exist to quantify the fire ball and its effects after the rupture, none is able to describe with accuracy the pre-rupture phenomena. This model is a work in progress, and at the end, the tool will take into account the two phases of the accident and will allow to study complete and consistent scenarios. After a description of the numerical model developed, this paper presents its application on the study of the influence of various parameters.
Domains
Engineering Sciences [physics]
Origin : Files produced by the author(s)
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