Nanocellulose explosions: influence of the agglomeration and turbulence on the combustion rate-limiting step and flame propagation

Abstract : Dust explosion risk assessment is relatively well established for micron-sized particles and requires the determination of key safety parameters representing the ignition sensitivity and explosion severity of the dust. When considering nanoparticles, the particle size distribution (PSD) is more likely to vary during the injection process, due to both the agglomeration phenomenon inherent to strong interactions and the fragmentation phenomenon due to flow shear stresses. As a consequence, safety parameters and their determination methods can differ significantly from micro to nanopowders. A peculiar attention has then to be given to the cloud characteristics (PSD, turbulence), more precisely at the exact moment of ignition. This work focuses on nanocellulose and aims at evaluating the influence of the agglomeration phenomenon and flow turbulence on the dust combustion. Flame propagation tests were performed to evaluate the unstretched burning velocity and explosions tests were carried out to estimate the combustion mechanisms involved.