| Composite insulators are widely used in transmission systems due to its favorable electrical properties.As the operation time of composite insulators increases,some of the insulators that have reached the service life gradually retire from operation.Recycling the increasingly large number of scrapped insulators has become a concern of power suppliers.The material of rubber housing used by composite insulator is mainly silicon rubber,which has high chemical stability and is difficult to be degraded naturally.The direct disposal of rubber housing material has a great impact on the environment.The recycle of rubber housing material is the key and difficult point in the recycle of composite insulator.In this paper,an efficient green method for recycling waste rubber housing is proposed:the silicone rubber material is recycled into the monodisperse nano-silica microspheres by the method of constant temperature pyrolysis.The whole recycle process has no harmful waste gas,the solid product is environmentally friendly and has a good application prospect.At the same time,the recycle of waste rubber housing also reflects the social responsibility of the power company.The main contents of this paper include:（1）Based on the method of constant temperature pyrolysis,to study the pyrolysis mechanism of the waste silicone rubber of rubber housing,the characteristic temperature and residual rate of the waste silicone rubber of rubber housing during the pyrolysis process were analyzed in detail by thermogravimetric analysis of the waste silicone rubber of rubber housing with different operating years;The composition of solid and gaseous products formed by pyrolysis was tested,and the physical and chemical reactions of waste silicone rubber of rubber housing during pyrolysis were analyzed in detail.The feasibility and environmental protection of recycling waste silicone rubber of rubber housing by pyrolysis were preliminarily verified,and the theoretical basis was provided for the pyrolysis synthesis conditions of nano-silica.（2）Through the analysis of the three key factors of pyrolysis process（calcined temperature,constant temperature time and heating rate）on the pyrolysis of the waste silicone rubber of rubber housing,the optimization of pyrolysis process recycling the waste silicone rubber of rubber housing into the spherical nano-silica was carried out.The pyrolysis process was determined as:heating up to 873 K at a rate of 10 K/min first,then holding 873 K for 1 h,and finally cooling temperature naturally;Based on the effect of pyrolysis process on the synthesis mechanism of spherical nano-Si O2,the multi-layer filter structure was designed to regulate the growth process of spherical nano-Si O2.By changing the number of filter mesh,spherical nano-Si O2 with different particle sizes could be obtained,and the minimum size of the obtained nano-Si O2 was 90 nm.According to the preliminary estimation,the electricity cost of the equipment in the pyrolysis process is only 1.38%of the economic value of the obtained nano-Si O2 microspheres,which is economically feasible.（3）The properties of produced nano-silica microspheres were studied.The excellent quality of the produced nano-silica was verified by comparing the physicochemical properties of produced nano-silica and commercial nano-silica.The produced nano-silica particles are standard spherical,and the spherical factor is up to 99.3%.The particle size distribution is uniform,with the range of particle size of 10 nm and the central particle size of 90 nm,belonging to the nanometer scale.Moreover,it has good dispersibility and no adhesion between particles,so it has high economic value. |
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