(71ah) Dust Explosion Kinetics

In this paper we propose a new method for analyzing dust explosion data. The standard approach is to determine K_st values from the explosion pressure histories obtained over a dust concentration range using a 20-liter spherical vessel. As an alternative, we treat the 20-liter sphere as a batch reactor and show how global kinetic parameters can be obtained from the same data by using an approach base on integral kinetic data. Global reaction rates are extracted from the pressure history data using chemical equilibrium calculations. Specifically, the method extracts both the concentration dependence and the temperature dependence for the global reaction rates. The results are expressed in terms of the functional dependence of the reaction rate on the concentration of fuel and oxidizer, and the temperature dependence is cast as an Arrhenius activation energy and pre-exponential factor. Although the approach can be used on a combustible dust sample of fixed chemical composition and just one particle size distribution, a more robust set of kinetic parameters can be obtained when samples of several different particle size distributions are tested. The methodology is demonstrated with aluminum dust test data.