Flame inhibition of coal dust with different particle sizes by Al(H2PO2)3 and Al2O3

• Published in: Fuel (Guildford) 2022-10, Vol.326, p.125001, Article 125001
• Main Authors: Yin, Hepeng, Dai, Huaming
• Format: Article
• Language: English
• Subjects: Coal dust deflagration; Coal gasification; Flame inhibition; Inhibitor powders
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2022.125001

•Flame characteristics of coal dust with different particle sizes under coal gasification were analyzed.•Inhibition performance of Al2O3 and Al(H2PO2)3 for coal dust deflagration was evaluated.•Flame intensity of coal dust was greatly weakened with Al(H2PO2)3 addition.•Coupled inhibition effect of Al(H2PO2)3 was revealed. To effectively mitigate coal dust/syngas deflagration accidents caused by leakage in a coal gasification scenario, inhibition experiments of flame propagation were conducted in a vertical combustion tube equipped with a high speed camera. And the inhibition performance of Al2O3 and Al(H2PO2)3 on deflagration of coal dust with different particle sizes was further investigated. The results showed that as the particle size of coal dust decreased, the flame intensity was enhanced first and then weakened. The flame propagation velocity and average degree of pulsation were the largest for 300 mesh coal dust, which were 23.90 and 7.32 m/s, respectively. After adding 80% Al(H2PO2)3 and Al2O3 to 200 mesh coal dust, the flame peak velocity decreased by 50% and 25%. And the flame was quenched and cannot propagate continuously under the inhibition of Al(H2PO2)3. The product analysis indicated that Al(H2PO2)3 generated PH3 and PO2 to dilute combustible substances in the reaction center and released heat-resistant phosphates to form an inorganic coating layer. Furthermore, the excellent inhibition performance of Al(H2PO2)3 was attributed to the scavenging of highly reactive radicals needed for combustion by P-containing radicals.