Experimental investigation and prediction model development for the minimum explosion concentration of tungsten dust in hydrogen environments

Abstract

The minimum explosion concentrations (MEC) of micrometer-size tungsten dust were measured in hydrogen environments with variable initial ignition energies. The results show that tungsten dust below the MEC will still explode mixed with hydrogen below the lower explosion limit (LEL) when the ignition energy is high enough, suggesting an interaction between the ignition energy and the concentration of the gaseous fuel. There is a discontinuity between the MEC curve of tungsten dust in hydrogen and the LEL point of hydrogen, which can not be explained by the ignition theory of volatile dust. On the basis of these phenomena, the ignition mechanism for the hybrid mixture of low-volatile dust/gaseous fuels was established, and a prediction model for the MEC of low-volatile dust in gaseous fuel environments was constructed. The work can provide essential parameters for explosion protection and theoretical support for dust process safety.