Effect of monoammonium phosphate particle size on flame propagation of aluminum dust cloud. (July 2019)

• Record Type: Journal Article
• Authors: Jiang, Haipeng; Bi, Mingshu; Gao, Wei
• Is Part Of: Journal of loss prevention in the process industries. Volume 60(2019)
• Page Start: 311
• Page End: 316
• Publication Date: 2019-07
• Subjects: Aluminum dust explosions -- Flame propagation behaviors -- Particle size distribution -- Surface kinetics; Chemical industries -- Safety measures -- Periodicals; 660.2804
• DOI: 10.1016/j.jlp.2019.05.009
• Languages: English
• ISSNs: 0950-4230

Abstract

Abstract: The effect of monoammonium phosphate (NH4 H2 PO4 ) particles on 5 μm aluminum dust flames is investigated experimentally and computationally. NH4H2PO4 in three particle size is employed to determine the inhibition efficiency on aluminum flame propagation. Flame inhibition mechanism considering both gas and surface chemistry of aluminum particles is developed. Results show that the inhibition effectiveness monotonously increases as NH4 H2 PO4 particle size is reduced to 25 μm. Flame morphology and flame microstructure change with the addition of different particle size NH4 H2 PO4 . Small NH4 H2 PO4 particles within the range studied have a greater reduction in average flame propagation compared to the coarser one. Meanwhile, the fine NH4 H2 PO4 particles almost decompose completely during the penetration of aluminum flame and then undergo a sufficient chemical interaction with the flame. The simulations indicate that the decomposition products of NH4 H2 PO4 particles obstruct the oxidation of aluminum particles through flame radical consumption. Additionally, the addition of NH4 H2 PO4 can reduce the vaporization rate and surface reaction rate of aluminum particles. Highlights: The effect of NH4 H2 PO4 particle size on inhibition effectiveness of aluminum flame is systematically investigated. The inhibition effectiveness monotonously increases as NH4 H2 PO4 particle size is reduce to 25 μm. Detailed inhibition mechanism accounting for both gas and surface chemistry are proposed.