Study on the flame propagation characteristics and mechanism of polyethylene dust deflagration suppressed by basic carbonates

• First application of basic carbonate for polyethylene deflagration suppression. • Basic zinc carbonate shows better inhibition effect than basic copper carbonate. • The inhibition mechanism of basic carbonate was revealed. This paper investigates the potential of basic copper carbonate (BCC) and basic zinc carbonate (BZC) as explosion suppressants for polyethylene (PE) dust deflagration , aiming to improve accident prevention and control. Specifically, this study examines the inhibitory effects and mechanisms of these substances on the flame propagation of PE dust. The effects of the two suppressants on the speed, time, and acceleration of PE flame propagation were compared through Hartmann tube experiments. The findings demonstrate that increasing the quantity of suppressant markedly reduces the rate of flame propagation. This effect is particularly evident when 60 wt% of BZC is introduced, resulting in near-complete suppression. BZC shows a stronger suppression effect compared to BCC, primarily attributable to its lower decomposition temperature, which facilitates earlier release of inert gases during the deflagration process, thereby inhibiting flame spread. Further analysis of the explosion products using FTIR and SEM revealed that the suppressants achieve flame inhibition through a dual mechanism of physical cooling and chemical free radical scavenging. Additionally, numerical simulations using CHEMKIN PRO demonstrated that the inert gases produced by the decomposition of BZC can effectively capture H and OH free radicals generated during combustion, reduce flame temperature, and inhibit chain reactions.