Scaling-up Metal Dusts Explosion Severity

Industrial explosions have been a hazard for as long as man has been processing, storing and transporting materials. Most of the reported dust explosions have involved organic products, mainly because most of the combustible materials in commerce are organic (agricultural, food, fuel, pharmaceuticals).

Nevertheless, this trend is changing due to the increase use of metals in the process industries (automotive, aeronautics, electronics). Metals have been reported in a growing number of severe dust explosions in China (Kunshan, 2014) and in the USA. It is noteworthy that metal dusts deflagrations lead to more severe burns and higher fatality rate due to higher flame temperature and thermal radiation.

For historic reasons, most of our knowledge on dust explosions has been obtained by studying agricultural fuels. Metal dusts, on the other hand, exhibit quite different combustion characteristics that are not well described in the dust explosion literature.

This presentation aims to investigate the special hazards and challenges posed by metal dusts based on recent deflagration experiments conducted at different scales (20-L and 1-m³Â contained tests, 2-m³Â vented tests) with different metal powders. Especially, it will be shown that metal dusts challenge the concept of scalability and well-established “cubic law” K_St = (dP/dt).V^1/3 used to design explosion protection techniques, such as venting.