Experimental study on the explosion and effect of explosion inhibiting of aluminum powder in medium-to-large-scale pipelines

In recent years, there have been frequent explosions of aluminum dust in the industrial and commercial enterprises, seriously threatening the personnel safety and economic development. To investigate the explosion characteristics of aluminum powder and the efficacy of explosion suppressant in industrial dust removal pipelines, a medium-to-large-scale transparent pipeline explosion testing system was constructed, and experiments on aluminum powder explosion and explosion suppression were carried out. Various parameters were measured under different influencing factors, including the explosion pressure, maximum free-field pressure rise rate, and the flame propagation speed. Through the analysis of pressure curves and deflagration flame propagation characteristics, the results showed that aluminum powder with a concentration below 100 g/m³ had a relatively low explosive destructive power in medium-to-large-scale pipeline. With increasing aluminum powder concentration, the mass of aluminum powder per unit volume rose. Consequently, more heat was released upon combustion. The flame propagated rapidly after passing through the second and third sections of the pipeline. The explosion pressure at each measurement point in the pipeline increased accordingly. Simultaneously, the free‑field pressure and its rise rate outside the pipeline increased significantly. A MgAl‑CO₃ bimetallic supramolecular suppressant suppresses aluminum powder explosion via physicochemical synergy. At a suppressant concentration of 500 g/m³, the free-field pressure of aluminum powder explosion decreased across all tested powder concentrations. Furthermore, the suppressant exhibited better performance for 300 g/m³ aluminum powder than for 200 g/m³, in terms of reducing both the maximum free-field pressure rise rate and flame propagation speed. At an aluminum powder concentration of 200 g/m³, the suppression effect remained almost unchanged with increasing suppressant concentration. However, an excessively high suppressant concentration reduced the suppression effect on the explosion free‑field pressure. The suppression effect of the suppressant interacts with the reaction acceleration caused by its high concentration, thereby reducing the overall suppression efficacy. Based on the engineering-scale pipeline testing system, these findings can provide scientific and theoretical support for the risk assessment and explosion suppression of aluminum powder explosions in industrial dust removal systems.