废旧复合绝缘子硅橡胶伞裙定值热解制备纳米二氧化硅的方法

Recovery and Preparation of Nano-silica by Pyrolysis From Waste Silicone Rubber Sheath of Composite Insulators

由于优异的耐污特性,复合绝缘子在我国电网中应用广泛,但是随着复合绝缘子使用年限的增长,退役复合绝缘子中包含的大量难以自然降解的硅橡胶材料将对环境造成极大的压力。为此基于定值热解法,提出了一种绿色回收废旧复合绝缘子得到高经济价值产物的方法。首先收集了运行20 a后自然退役的复合绝缘子伞裙材料,详细研究了硅橡胶材料的热解过程以及固体、气体副产物,初步验证了方法的可行性。然后对比了不同加热温度以及不同保温时间的产物理化特性,并基于超微颗粒生长模型,得到了最优的热解工艺参数。最后对所得纳米粒子进行了纯度、粒径分析,并与商用白炭黑进行了对比。研究结果表明:定值热解法可以绿色分解废旧硅橡胶材料,在700℃、恒温120 min的情况下,所得纳米二氧化硅中心粒径为160 nm,纯度超过97%,且微粒尺寸均匀,外形光滑,性能超过商业白炭黑。

Due to its excellent pollution resistance, composite insulators are widely used in China’s power grid. However, with the growth of the service life of composite insulators, a huge number of silicon rubber materials which are difficult to degrade naturally from decommissioned composite insulators will bring great pressure on the environment. In this paper, based on the method of pyrolysis, a green method of recycling waste composite insulators to obtain high economic value products is proposed. Firstly, the composite insulator silicon rubber materials, which were naturally decommissioned after 20 years of operation were collected. The pyrolysis process of the silicone rubber material and the products of the solid and gas were studied in detail, which preliminarily verified the feasibility of the method. Then the physicochemical properties of products at different heating temperatures and socking time were compared, and the optimal parameters of the pyrolysis process were obtained based on the growth model of ultrafine particles. Finally, the purity and particle size of the nanoparticles were analyzed and compared with commercial silica. The research results show that the waste silicone rubber materials can be greenly decomposed by pyrolysis. Under the condition of 700 ℃ for 120 min, the central particle size of nano-silica is 160 nm, the purity is more than 97%, the particle size is uniform, the shape is smooth, and the performance is better than commercial silica.