Blanchard R., Schildberg H., 2013, Sizing of Explosion Pressure Relief for Gases with Low KG Values using the Efflux Function, Chemical Engineering Transactions, 31, 667-672.
Determination of deflagration venting requirements in chemical/process plants is usually carried out using well established standards employing an empirically based formula. However, this formula is shown to have severe shortcomings in the range of low KG-values, where either negative or inconceivably large venting areas can be predicted. Due to these shortcomings a method has been developed using the efflux function for gases as a basis to predict the mass flow through a vent opening in a vessel during an internal explosion. The simulated rise in pressure due to the internal explosion is quantitatively determined from the KG value, with the mass flow through the vent opening in the vessel resulting from the pressure difference between the vessel and its surroundings. This enables the maximum overpressure as a function of the pressure relief surface area to be predicted. The method takes account of the temperature of the efflux gases, and turbulence enhancement brought about by the venting process. The development, validation and limitations of this new method are presented along with suggestions for its further development.
