Suppression of polyethylene dust deflagrations by sodium bicarbonate, melamine cyanurate ( MCA ), melamine polyphosphate ( MPP ), and MCA–MPP mixtures

Abstract Polyethylene (PE) dust can pose an explosion hazard during industrial processing and handling, such as during conveying into silos, with the hazard level depending strongly on particle size. To improve suppression performance, this study investigated the effects of single‐component suppressants (sodium bicarbonate, NaHCO 3 ; melamine cyanurate, MCA; melamine polyphosphate, MPP) and MPP–MCA composite powders with various mass ratios on the explosion characteristics of high‐density polyethylene (HDPE) dust. Explosibility tests, flame propagation experiments, thermogravimetric analysis (TG‐DTG), and differential scanning calorimetry (DSC) were conducted to evaluate suppression performance and pyrolysis behavior. Results show that MPP had the best suppression efficiency among the three inhibitors, followed by MCA, while NaHCO 3 performed the worst. All three inhibitors exhibited a suppressant‐enhanced explosion parameter (SEEP) effect at low addition ratios. MPP–MCA composites demonstrated significant synergistic suppression, with the 3:1 mass ratio formulation showing superior performance, effectively reducing maximum pressure, pressure rise rate, and flame propagation extent. These findings provide insights for designing composite suppressants and offer experimental support for mitigating polyethylene deflagrations in air‐suspended dust processes. The inerting powders may be used for suppressing incipient explosions in equipment containing explosive dust–air mixtures.