Influence of Particle Size on the Flammability and Explosibility of Biomass Dusts: Is a New Approach Needed?

The influence of particle size on the flammability and explosion severity has been widely demonstrated for coals along the years: the thinner the particle size, the more flammable is the dust and more severe are the explosions. Later, the increase on the use of biomass led to using the same resources and techniques for both groups of materials, considering them similar enough. However, there are basic differences between biomass and coal dust particles that leads to different behaviours when focusing on industrial fire safety. This difference is the starting point of this review, where a study on the existing knowledge in relation to the size and shape of biomass dust is presented. The methodologies and parameters used to determine particle size are described and discussed, showing the inconvenience of using only one parameter (d₅₀) to describe dust, as well as the need of a standardized methodology to homogenise the results. The biomass data gathered from scientific literature and the following analysis carried out has also highlighted the importance of identifying samples in an accurate way and the strong necessity of further research on these materials and on the interdependence between particle size and the experimental procedures for flammability and explosibility properties.