Influence of ignition source on the dispersed dust clouds

Abstract. Combustible dust present in industrial processes represents a significant hazard due to its potential for accidental ignition and subsequent explosion. The evaluation of such risks is generally accomplished using standardised laboratory tests, such as measurement in the 20-litre chamber. However, it is important to note that the characteristics of the ignition source used in these tests can significantly affect the measured parameters and the resulting safety data. The present study focuses on the effect of different igniters on the dispersion and combustion of lycopodium dust clouds. Reproducible and controlled dust dispersion was achieved through the Hartmann tube dispersal system. High-speed imaging techniques were used to observe dust dispersion, ignition, and flame propagation. The results demonstrate that the type of igniter used has a substantial influence on the combustion of the dust cloud. The standardised Sobbe igniter (500 J; 2000 J; 5000 J) had a significant impact on the dispersion process, while the electric igniter caused minimal turbulence. These findings highlight the importance of ignition source selection in the interpretation of explosivity data from standardised tests. Consideration of this factor is essential for improving the accuracy of dust explosion assessments and for advancing safety practices in the industrial environment.