Effects of explosion suppressants on the dust explosion and pyrolysis characteristics of the fungicide fenaminstrobin

Abstract

In this study, the explosion and pyrolysis characteristics of fungicide fenaminstrobin dust were studied, and the inhibitory effects of three explosion suppressants, namely, NH4H2PO4, KH2PO4, and KCl, on dust explosion were compared. A combined thermogravimetric (TG)–Fourier transform infrared (FTIR)–mass spectrometry (MS) technique was adopted to analyze the inhibition mechanism. The results showed that the minimum ignition energy (MIE) was 5 mJ, the explosion index (Kst) was 305.7 bar m/s, and the dust explosion hazard was severe. We found that all three compounds (NH4H2PO4, KH2PO4, and KCl) could be used as explosion suppressants. When the addition dose of NH4H2PO4 was 35%, the Kst value dropped by 40.7%, and MIE exceeded 1000 mJ. When the addition of KH2PO4 was 50%, the Kst value dropped by 37.3%, and the MIE increased to 300 mJ. In comparison, NH4H2PO4 showed the best inhibitory effect, while KCl demonstrated the worst inhibitory effect. The pyrolysis of fenaminstrobin produced organic gases, including quinoline, benzonitrile, and methyl isocyanate, and generated large quantities of free radicals. The explosion suppressants could inhibit the explosion through physical pathways (endothermic, coating, and oxygen-diluting processes) and chemical pathways (free-radical capture).