Hydrocarbon aerosol explosion : towards hazardous area classification

Stéphanie El-Zahlanieh (1) , Augustin Charvet (1) , Alexis Vignes (2) , Benoît Tribouilloy (2) , Olivier Dufaud (1)

1 LRGP - Laboratoire Réactions et Génie des Procédés
2 INERIS - Institut National de l'Environnement Industriel et des Risques

Assessing the risk of formation and ignition of explosive atmosphere (ATEX) associated with the generation of a flammable aerosol is required by European ATEX regulation. However, such risk analysis sometimes proves difficult because of the lack of tools correlating the dispersion conditions of a mist cloud with its flammability and explosivity. This work aims to define objective criteria for assessing the risk related to the hydrocarbon mists explosion within the framework of hazardous area classification. Different fluids were selected according to their industrial interest and their physicochemical characteristics; here, a volatile solvent (ethanol), a lubricating oil and kerosene. Existing experimental set-ups as the 20L sphere and the modified Hartmann tube were adapted to determine the flammability and explosion severity of sprays and mists. A sensitivity study was performed as a function of influential parameters such as the fluid composition, the generation mode, the pressure and the turbulence. The time evolution of droplet size distributions was determined by in situ laser diffraction and APS spectrometry (aerodynamic diameter measurement). The flammability study was focused on the determination of the Lower Explosive Limit and the Minimum Ignition Energy. In parallel, the study of the flame propagation in a semi-open tube was used to qualify the effects of the turbulence/combustion interactions. Some tests were also performed in a standard 20L explosion sphere to determine the maximum explosion pressure and maximum rate of pressure rise of specific mists. Finally, these experimental results could serve as an input for reactive CFD simulations aiming at predicting the consequences of aerosol explosions. From a practical point of view, this study should provide decision support tools for hazardous area classification, especially for the definition of the flammable cloud extent on the basis of a percentage of the lower explosive limit.

Keywords: AEROSOL; SPRAY; EXPLOSION; FLAME PROPAGATION; HAZARDOUS AREA CLASSIFICATION

Domains: Risques; Reactive fluid environment

Stéphanie El-Zahlanieh, Augustin Charvet, Alexis Vignes, Benoît Tribouilloy, Olivier Dufaud. Hydrocarbon aerosol explosion : towards hazardous area classification. 13th International symposium on hazards, prevention, and mitigation of industrial explosions (ISHPMIE 2020), Jul 2020, Braunschweig, Germany. pp.572-583, ⟨10.7795/810.20200724⟩. ⟨ineris-03319939⟩