Abstract:

A new gel-type fire extinguishant with core-shell structure is designed which aims at the integrated innovation in the form of the extinguishant to overcome the shortcomings of environmental protection, efficiency and corrosiveness of traditional extinguishant. The gas-phase silicon dioxide, aqueous ammonium dihydrogen phosphate solution, gellan gum and methyl hydrogen silicone combined to prepare the extinguishant by high-speed shearing method. The pressure resistance and fire extinguishing effectiveness of the extinguishant are characterized, and the synergistic mechanism of the extinguishant is studied. The obtained results show that the damage rate is minimal when the size of as-prepared particles ranged between 100—200 μm and the exerting pressure is less than 1.2 MPa.The extinguishant has better performance in suppression class A fire and played a synergistic effect in the process of fire extinguishing: the water acts as an inert component which could evaporate rapidly and cool down the fuel; the ammonium dihydrogen phosphate acts as a chemical component which decomposed by heat absorption and capturer a dicals of the flame for cutting the chain reaction. The gel adheres to the wooden surface and forms an isolation layer, the smoldering and resurgence are inhibited by continuous cooling. Fire-extinguishing performance of gel-type core-shell structure powder fire extinguishing medium is better than that of ordinary ABC dry powder, and the cost is lower, which has a good application prospect.

Key words: gels, powders, core-shell structure, preparation, class A, efficiency

摘要：

通过设计一种凝胶型核壳结构粉体灭火介质，旨在灭火剂剂型上进行集成创新，克服传统灭火剂在环保、效能以及腐蚀性上的不足。利用高速剪切法将气相二氧化硅、磷酸二氢氨溶液、结冷胶与甲基含氢硅油相结合制备该介质，并对其耐压性和灭火有效性进行表征，研究介质的协同作用机理。结果表明：该介质的粒径在100~200 μm并且充装压力不大于1.2 MPa时的破损率最小。该新型介质具有较好的抑制熄灭A类火的效能，并且在灭火过程中能够发挥协同作用：水作为惰性灭火组分能够迅速蒸发冷却降温；磷酸二氢铵作为化学灭火组分分解吸热并捕捉燃烧反应自由基，切断链式反应扑灭火焰；凝胶能附着在木垛表面形成隔离层，持续降温抑制阴燃和复燃。凝胶型核壳结构粉体灭火介质的灭火效能优于普通ABC干粉，且成本更低，有较好的应用前景。

关键词: 凝胶, 粉体, 核壳结构, 制备, A类, 有效性