煤粉—惰性介质混合体系爆炸特性实验研究

为深入认识煤粉—惰性介质混合体系爆炸行为,在Siwek 20 L球形爆炸测试系统内研究了煤粉—惰性介质混合体系的爆炸威力(最大爆炸压力、最大升压速率、燃烧持续时间)、敏感度(爆炸上、下限)和惰性介质的抑爆效力,并重点考察了点火能量、煤粉热值、惰性介质组分、煤粉浓度、煤/惰性介质混合比等因素的影响。结果表明,添加惰性介质能显著降低煤粉爆炸威力,其抑爆效力随点火能量增加而下降,并由此建议采用5～10 kJ点火能量考察惰化效应;煤粉热值增加可显著提高混合体系的爆炸威力;就惰化效应而言,湿分的抑爆效力优于磷酸二氢铵和碳酸钙,而磷酸二氢铵的抑爆效力又优于碳酸钙,其中煤粉完全惰化所需惰化剂量与煤尘浓度密切相关,在200～400 g/m3处有最大值,为"最危险浓度";增加惰性介质添加量可降低爆炸上限,提高爆炸下限,有效压缩煤粉尘可爆浓度范围。研究结果对深入理解粉尘爆炸规律、优化惰化标准,完善测试方法有参考价值。

Experiment-based Investigations on Explosion Behaviors of Coal Dust-inertant Mixtures

To gain an insight into the explosion behavior of coal dust-inertant mixtures, systematic experiments were carried out on explosion severity (the maximum explosion pressure, the maximum rate of pressure rise and the combustion duration), sensitivity (the higher and lower explosion limits) and inertant inerting effectiveness by using a Siwek 20 L spherical explosion test system. Influences of ignition energy, coal dust calorific value, inertant composition, dust concentration and mixing ratio of coal/inertant were taken into account. Results show that the addition of inertant into the coal dust can mitigate the explosion brisance effectively. The inerting effectiveness of inertant decreases with ignition energy and becomes stabilized when ignition energy exceeds to 5 kJ, which suggests that the ignition energy region of 5-10 kJ be appropriate for inerting testing. The inerting effectiveness of inertant is reversely related to coal dust calorific value. For the inerting of coal dust explosion, the moisture shows the best result, followed by the Monoammonium phosphate and calcium carbonate. The inertant amount required for fully inerting is related to the coal dust concentration and when the coal dust concentration reaches to the worst-case concentration (between 200-400 g/m3), the maximum amount of inertant will be required. It is also found that the addition of inertant reduces the higher explosion limit and raises the lower explosion limit of the coal dust, leading to a narrowed explosible concentration region.