Study on the variation regularities of minimum explosion concentration of moist magnesium dust/derived hydrogen hybrids under multiple working conditions

Magnesium is widely used but often accompanied by frequent magnesium powder explosion accidents. If the variation regularity and mechanism of the minimum explosion concentration (cm) of magnesium powder under the multi-factor coupling effect can be understood, the occurrence of magnesium powder explosion accidents can be fundamentally avoided, and intrinsic safety can be achieved. In this paper, experiments were conducted using a self-made 20 L explosion device to explore the effects of particle size, initial temperature, and equilibrium relative humidity (ERH) coupling on the cm of magnesium powder. The study found that an increase in ERH of moist magnesium powder would lead to easier agglomeration of the dust, making it less prone to activation. Additionally, excessive moisture also absorbed more heat, reducing the ignition sensitivity of the dust cloud and resulting in a continuous increase in cm. However, increasing the initial temperature and decreasing the dust particle size both decreased the cm of moist magnesium powder, weakening the effect of ERH on cm. Furthermore, using the analysis methods of orthogonal experimental range and AHP model, it was determined that the influence weights of the factors coupling effects on the cm of magnesium powder, from highest to lowest weight, were: particle size > ERH > initial temperature.Furthermore, in order to deeper understand the mechanism of the action process that affect the cm of moist magnesium powder, additional experiments were conducted to further confirm that the addition of hydrogen derived from the erosion reaction of moist magnesium powder to the explosion system can reduce the cm of magnesium dust clouds. Moreover, a quantitative mathematical model for predicting the cm of magnesium powder/hydrogen two-phase system was also established.