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[Display omitted] In order to develop a green and efficient nano suppressant for aluminum (Al) dust explosion, MCN with layered structure was synthesized with low-cost urea as precursor via simple calcination technology. The suppression performance of MCN on the flame propagation of 30 μm and 5 μm Al dust with the concentration of 1000 g/m3 was experimentally studied. Results showed that with the addition of MCN increasing, the flame luminous intensity, flame propagation velocity and fluctuating trend of mixture-Al dust were greatly decreased. After adding 500 g/m3 and 700 g/m3 to 30 μm and 5 μm Al dust, the average flame propagation velocities declined by 73.24 % and 94.07 % separately. The minimum inerting concentration of 30 μm and 5 μm Al dust was 600 g/m3 and 900 g/m3. Explosion residuals were analyzed to further reveal the suppression mechanism of MCN in detail. The good performance of MCN provided a potential direction to develop efficient suppressants on the suppression of Al dust explosions to improve process safety. [ABSTRACT FROM AUTHOR]

The flame behavior and pressure characteristics of vented propane-air explosions at elevated static activation pressures (P stat) were investigated in a duct with a length-to-diameter (L/D) ratio of 7. The impact of the discharge traction and the coupling effect of the internal flame front and pressure waves on the flame propagation behavior were captured. The effect of increasing P stat on the vented flame length and width under a fixed vent was weak. The influences of P stat on the pressure profiles and maximum reduced pressure (P red) were investigated. The increase of P stat mitigated the blocking effect of external explosion on P red and further promoted the discharge pressure drop rate to be controlled within the limit of the discharge capacity of the vent. The formation mechanisms of the two main external pressure peaks were analyzed. For the larger D v conditions, the sensitivity of high P stat to the increase of maximum external pressure was higher than that of low P stat. A modified model of P red was developed considering the effects of elevated P stat and vent coefficient K V , which is proved to have a good performance in vented explosion ducts with a large L/D ratio. [ABSTRACT FROM AUTHOR]

Lysine sulfate (LS) powder is at high risk of fire and explosion during its production, processing and storage. Considering its edible and nutritive values, the selection for its explosion inhibitor requires both excellent inhibition performance and environmental friendliness. The inhibition performance of a natural food additive of sodium phytate (SP) on LS dust deflagration is investigated by comparing it with ammonium polyphosphate (APP), which is a widely used flame retardant. The deflagration characteristics of LS mixtures with various mass fractions of SP and APP are recorded by high-speed photography and fine thermocouples. The combustion heat is tested by micro-scale combustion calorimetry. Thermal stability of samples are studied by using a synchronous thermal analyzer. The results show that the deflagration of LS dust is completely suppressed when the mass fractions of APP and SP increase to 2% and 8%, respectively. The corresponding inhibition mechanisms are proposed based on the dust deflagration macroscopic results and microcosmic analysis on thermal decomposition products and residuals. These findings may provide a solution to reduce the probability and damage of dust explosions. [ABSTRACT FROM AUTHOR]