镁铝水滑石抑制聚乙烯粉尘爆炸特性与机理

为寻求新型、清洁、高效的聚乙烯粉尘爆炸抑制剂，将镁铝水滑石用于聚乙烯粉尘爆炸抑制，并从爆炸超压和最低着火温度两方面，分析了镁铝水滑石抑制聚乙烯粉尘爆炸特性，并与氢氧化铝、氢氧化镁进行对比。结果表明，镁铝水滑石对聚乙烯粉尘爆炸超压和最低着火温度的抑制作用均优于氢氧化铝和氢氧化镁。在爆炸超压的抑制方面，在抑制比为2时，镁铝水滑石可完全抑制聚乙烯粉尘爆炸，而氢氧化铝和氢氧化镁对聚乙烯达到完全抑爆所需的抑制比分别为4和5。最低着火温度的抑制方面，抑制比为1时，镁铝水滑石可使聚乙烯粉尘的最低着火温度提高290 ℃，大于氢氧化铝的260 ℃和氢氧化镁的250 ℃。此外，结合镁铝水滑石的热解特性及红外光谱，从物理作用和化学作用两个方面对聚乙烯粉尘爆炸的抑制机理进行分析，揭示了阻断爆炸反应的进程。

Suppression characteristics and mechanism of polyethylene dust explosion by Mg-Al hydrotalcite

In order to find a new, clean and efficient inhibitor of PE dust explosion, the Mg-Al hydrotalcite was used to inhibit PE dust explosion by using standard 20 L spherical explosion test system and minimum ignition temperature test system of dust cloud. The inhibition properties of Mg-Al hydrotalcite for PE dust explosion are analyzed from the aspects of explosion overpressure and minimum ignition temperature, and are compared with aluminum hydroxide and magnesium hydroxide. The results showed that the inhibition effect of Mg-Al hydrotalcite on explosion overpressure and minimum ignition temperature of polyethylene dust is superior to that of aluminum hydroxide and magnesium hydroxide. In terms of explosion overpressure, when the inhibition ratio is 2, Mg-Al hydrotalcite can completely inhibit the explosion of polyethylene dust, while the inhibition ratios required for aluminum hydroxide and magnesium hydroxide to achieve complete explosion suppression of polyethylene are 4 and 5 respectively. With the increase of inhibition ratio, the maximum explosion pressure rise rate of polyethylene dust decreased. The inhibition effect of Mg-Al hydrotalcite on the explosion pressure rise rate of polyethylene dust is also better than that of aluminum hydroxide and magnesium hydroxide. In terms of minimum ignition temperature, when the inhibition ratio was 1, Mg-Al hydrotalcite increased the minimum ignition temperature of polyethylene dust to 710 ℃, which was 290 ℃ higher than that of pure polyethylene dust. Under the same conditions, aluminum hydroxide and magnesium hydroxide can increase the minimum ignition temperature of polyethylene dust by 260 ℃ and 250 ℃ respectively. Therefore, the inhibition effect of Mg-Al hydrotalcite on the minimum ignition temperature of polyethylene is also greater than that of aluminum hydroxide and magnesium hydroxide. In addition, the inhibition mechanism of Mg-Al hydrotalcite on polyethylene dust explosion was analyzed based on its pyrolysis characteristics and infrared spectra.The physical effect is mainly realized by absorbing heat from the reaction system and diluting the oxygen concentration. The chemical action is mainly achieved by the pyrolysis products carbon dioxide and water participating in and blocking the polyethylene explosion chain reaction.