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Chronicles of Incidents and Response
Published in Robert A. Burke, Chronicles of Incidents and Response, 2020
The explosion that occurred at the farm is known as a Boiling Liquid Expanding Vapor Explosion or BLEVE. A BLEVE can occur when a pressure vessel containing a flammable liquid, like a propane tank, is exposed to fire. The book, Loss Prevention in the Process Industries, provides the following description of a BLEVE:
Fundamentals of Source Assessment
Published in Jack Daugherty, Assessment of Chemical Exposures, 2020
A special kind of explosion, the nightmare of every fireman and emergency responder, is the BLEVE (pronounced BLEH–vee). The acronym BLEVE stands for Boiling Liquid Expanding Vapor Explosion, which is descriptive of the chain of events leading to the explosion. An external flame or radiant heat from an external fire impinges on the surface of the tank, heating the liquid contents and raising its vapor pressure. As the walls heat up, the structural integrity of the tank is weakened. Eventually, the liquid reaches its boiling point and the vapor pressure is atmospheric or greater depending on whether some vapor escape rapidly enough. When the last of the liquid is boiled off, the vapor is superheated and, with the right amount of oxygen, an explosive mixture is created. The tank then becomes a huge bomb. The BLEVE itself is the explosive vaporization of the remaining vessel contents, often followed by the combustion of the vaporized cloud that preceded it. If you have never seen a BLEVE , several good videos are available from training video vendors and fire departments. First, the tank explodes, then, depending on whether the liquid is combustible, the vapor cloud explodes. Double whammy of catastrophic proportions. As said earlier, BLEVEs are every emergency responder’s worst nightmare.
Risk Assesment
Published in Srinivasan Chandrasekaran, Offshore Structural Engineering, 2017
A BLEVE is explosively expanding vapor or two-phase fluid. A BLEVE results from a “hot rupture” of a vessel typically containing hydrocarbons such as LPG, etc., stored and maintained as a liquid under pressure, due to an impinging or engulfing fire. A flammable material will be ignited immediately upon rupture by the impinging/engulfing fire and will burn as a fireball. A fireball would also result from the immediate ignition of a release resulting from the cold catastrophic rupture of a pressurized vessel. The initial phase of a gas pipeline rupture should also be modeled as a fireball.
Thermodynamic properties and explosion energy analysis of carbon dioxide blasting systems
Published in Mining Technology, 2019
Bo Ke, Keping Zhou, Chaoshui Xu, Gaofeng Ren, Tingting Jiang
This article presents the results of an experimental study of carbon dioxide blasting. Based on the results, the following conclusions can be drawn: The rate of temperature change increases as the initial density of CO2 decreases and the temperature rises faster when the initial temperature is higher. The graph of temperature variations appears as a concave exponential curve initially, then rapidly increases linearly, followed by a gentle increase.The effect of the initial density of CO2 on isochoric heat capacity appears to be significant. The smaller the initial density, the larger the peak specific heat capacity at the critical temperature. The variation of the specific isochoric heat capacity can be used to divide the temperature curve into four stages. The specific isochoric heat capacity and its rate of change determine the increasing rate of temperature.Based on the pressure curve of CO2 blasting, the process can be divided into three stages: the pressure rise stage, the pressure release stage and the pressure recovery stage. The period of time for the pressure rise stage is about 0.026–0.086 s, and that for the pressure release stage is about 0.00018–0.00026 s. In terms of the mechanism of pressure response and phase transitions of CO2 within the tube, the tube is initially filled with high-density fluid and low-density gas. When the heater is activated, the heat is transmitted to the CO2 and temperature and pressure increase, causing the CO2 to enter the supercritical state. When the internal pressure exceeds the strength of the rupture disc, the disc breaks, causing the high-pressure supercritical CO2 to be released from the tube with a rapid depressurisation. The entire process is termed the Boiling Liquid Expanding Vapour Explosion (BLEVE).Using the Span and Wagner CO2 EOS and the thermodynamics of explosion, the proposed method can be used to calculate the explosion energy of CO2 blasting systems. As discussed above and demonstrated using figures measured in our experiments, the calculation results are more accurate for carbon dioxide blasting systems.