Predictive method of pressure venting for dust explosions in large vessels

A simple modelling easily usable in the industrial environment has been pre viously described in order to predict the evolution of the combustion chara cteristics of solid-gas mixtures in a closed vessel. The aim of this work c onsists in extending the model development to a wide range of dust suspensi ons in the general case of vented explosions and to test. the model behavio ur to get a risk evaluation and improve safety conditions in industrial pla nts. A simple representation of the combustion phenomena based on energy tr ansfers between particles and the action of specific molecules is presented . The pressure venting due to the vent breaking is calculated from thermody namical characteristics given by the model anti taking into account the mas s I ate of discharge of the different products deduced from the standard or ifice equations. The application conditions determine the fuel ratio of the used mixtures, the nature of the chemical kinetics and the calculation of a universal set of parameters. The proposed development is compared to Bart knecht's experimental results and shows the model representativeness for va ried dust suspensions (cornstarch, cellulose and aminophenazone) in very la rge use conditions such as the concentration in a rich or a lean mixture, t he vessel volume or its geometry and the choice of the vent area or the ven ting pressure. The first results indicate correct tendencies in the predict ions and it seems interesting to precise this evaluation in the future with vented gaseous mixtures.