BLEVE

BLEVE

BLEVE

BLEVE (boiling liquid expanding vapor explosions) is defined as an incident that arises from the diminution in the stress which could be yielded by the wall of a pipe or a vessel, which does not have the strength of containing the level of stress imposed on it, this strength of containing the liquid is hugely influenced by the way the container has been constructed along with the relieve value of the set points of the container. This failure in containing the liquid often results in a violent discharge of the liquid present inside the container in the form of extremely rigorous fireballs (BLEVE Research, (2004).

Even after so many years researchers have failed to identify the phenomenon behind the mechanism of BLEVE. However, some literature work, in the form of theories has been conducted regarding this phenomenon, but most of them were mainly based on the phenomenon of the overheating of the liquid. These theories suggests due to sudden depressurization of the liquid, when it is in a momentarily superheated state causes homogenous nucleation throughout the bulk of liquid, this process changes the form of liquid to vapor which occurs at a very high rate. This causes the explosion of the superheated liquid. Reid [5] has linked this hypothesis along with the strength of the explosion, which is immediately followed by a failure in the tank containing the liquid; this failure is caused by the extreme degree of superheated liquid present inside the tank.

The phenomenon of BLEVE (boiling liquid expanding vapor explosions) occurs as the result of an experiment, in which the liquid present inside the container reaches a level of temperature which is well above the boiling point of the liquid at a certain atmospheric temperature, which causes the rupturation of the vessels in more than two pieces. The boiling liquid expanding vapor explosions takes place by the impingement of fire on the LP tank shell at the points which are well above the level of contents of the LP tank. As a result of this impingement the metal surface inside the tank starts to wear off, which results in the failure from the internal pressure of the tank.

Along with that the boiling liquid expanding vapor explosions could also cause some major damages to the mechanical structure of the tank. This damage can occur as the result of a traffic accident, or by the derailment of train. In case a BLEVE occurs, the debris of the tank may travel to hundreds of feet from the place of accident, and this debris travels with a tremendous amount of force, which causes the fuel to escape the tank, this becomes the reason of expanding huge fireballs as a result of fuel ignition.

According to some previous observations it was observed that most of the liquefied gas BLEVE occurred due to fire exposure to the tank, while in some cases BLEVE occurred as a result of container failures and certain other causes such as corrosion. The impact of failures is particularly perceptible ...