变压器油高温裂解及油中酸影响机理的反应分子动力学模拟

发布时间：2019-08-16 10:52

【摘要】：变压器油热裂解是其内部绝缘缺陷发生时的主要降解形式之一,以16个C原子数的烃分子为例,引入反应力场(Reax FF)反应分子动力学方法对其高温下的裂解反应及油中酸的影响进行了模拟,从原子层面揭示其微观反应动力学机理。统计不同温度下裂解过程的反应物和生成物变化,结果表明:随着温度升高,3类反应物裂解速度均明显加快;裂解的主要生成物为C2H4、C3H6、CH3、H2、C2H5、C2H6、C2H3等小分子烃或自由基,各温度下C2H4均为数量最多的产物,且在达到饱和之前基本呈线性增长;随着温度的升高,裂解生成的小分子烃的不饱和度增加,H2质量分数也明显增多。对添加甲酸的变压器油裂解过程模拟表明:随着甲酸质量分数的提高,生成H2的数量成正比增加,且其生成量与甲酸的减少量相一致;反应路径分析表明酸性环境下H2的生成主要和甲酸羟基的H与烃类的H发生反应有关,这也是甲酸加速变压器油裂解的原因。
[Abstract]:Transformer oil pyrolysis is one of the main degradation forms of internal insulation defects. Taking 16 C atom number hydrocarbon molecules as an example, the reaction field (Reax FF) reaction molecular dynamics method was introduced to simulate the cracking reaction and the influence of acid in oil at high temperature, and the microscopic reaction kinetics mechanism was revealed from the atomic level. The results showed that the cracking rate of the three reactants increased obviously with the increase of temperature, and the main products of pyrolysis were C2H4, C3H6, CH3, C2H5, C2H6, C2H3 and other small molecular hydrocarbons or free radicals. C2H4 was the largest number of products at all temperatures, and increased linearly before reaching saturation. With the increase of temperature, the unsaturation of small molecular hydrocarbons produced by pyrolysis increases, and the mass fraction of H2 increases obviously. The simulation results of transformer oil cracking process with formic acid show that with the increase of formic acid mass fraction, the amount of H2 formed is proportional to the decrease of formic acid, and the reaction path analysis shows that the formation of H2 is mainly related to the reaction of formic acid hydroxyl group H with hydrocarbon H, which is also the reason why formic acid accelerates the cracking of transformer oil.
【作者单位】：国网山东省电力公司电力科学研究院;华北电力大学电气与电子工程学院;河北电力科学研究院;
【基金】：国家自然科学基金(51477051) 北京市自然科学基金(3142018)~~
【分类号】：TM41

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