Experimental Study on Influence of Nitrogen Concentration in Air on Minimum Ignition Energies of Combustible Powders

As useful method to prevent dust explosions, inerting using nitrogen (N₂), which is an incombustible gas, has been used in industries. This paper is a report of the relationship between the minimum ignition energy (MIE) of powders due to an electrostatic sparks and the minimum oxygen concentration (MOC) for combustion. In this paper, we have changed the N₂ amount in the air in order to control the oxygen concentration. The Hartman vertical-tube apparatus was used in this study. The control range of the dust concentrations of the MIE apparatus used in this study is from 0.5 kg/m³ to 1.5 kg/m³. The maximum spark energy achieved in this study was 1000 mJ. Five polymer powders were used in the experiment. As a result, the inerting of N₂ has an effect on the ignitability of sample powders. The MIE of all powders used in this study increased due to the increase in the amount of N₂ in the air.