Investigation of marginal explosibility of organic dusts in the 20-L and 1-m3 explosion chambers

Abstract

Experimental research has been conducted to investigate the explosibility behaviour of the so-called marginally explosible dusts, using well-calibrated standard apparatus and ASTM standard procedures. These dusts have been defined based on a KSt value ≤ 45 bar.m/s in the 20-L chamber and there are uncertainties about their explosibility on the industrial scale. Out of the 4 dust samples tested, Pmax and KSt values from 3 showed good correlation between the 20-L and 1-m3 chamber, except for coarse polyethylene. This sample could not be classified as marginally explosible despite its low KSt (23 bar.m/s) in the 20-L. It was clearly explosible as confirmed by its KSt value in the 1-m3 chamber (72 bar.m/s), measurable MEC (<100 g/m3) and MIT (420 oC) values. Thus, it was concluded that definition of marginal explosibility based on a KSt value from the 20-L may not be entirely accurate since explosibility behaviour differs for different materials.