【作者】 杨凤；

【导师】 孙大贵；

【作者基本信息】 重庆大学 ， 化学， 2010， 硕士

【摘要】 在油浸电力设备中得到广泛应用的矿物绝缘油,具有良好的电气绝缘和冷却性能以及低廉的成本。但是,矿物油难以生物降解,一旦泄漏将会对水源、居住环境等造成污染,无法达到环保绝缘材料的要求。因此,研究环保型液体绝缘介质成为国际上关注的新课题。植物绝缘油的研究与矿物油的研究是同期进行的。早期由于植物绝缘油的抗氧化性能较差、粘度大,因此仅被用作电容器的浸渍剂。自上世纪90年代以来,植物型液体绝缘介质的研究重新受到许多科学工作者的重视。植物油来源于天然的油料作物,可完全生物降解。在石油枯竭的新形势下,它将可能成为矿物油的绿色替代品。实验采用菜籽油作为原料油、甲醇作为酯交换的小分子醇,在微波辐射和离子液体的催化作用下,高效、快速制备了植物绝缘油。研究了微波功率、微波辐射时间、离子液体的用量、催化剂的种类及用量、醇油物质的量比等对绝缘油制备的影响。研究结果表明,用碱作催化剂时,微波和离子液体对绝缘油的制备有协同促进作用。离子液体具有催化与增溶的作用,能较好地消除醇-油间的界面接触,减小皂化现象,提高酯交换效率,而微波加热的热效应和非热效应能加快酯交换速率。多次实验结果表明,微波法制备绝缘油的最佳工艺条件为微波功率为1000W,微波辐射时间为10min,微波温度为65℃,醇油物质的量比为6:1,催化剂NaOH的用量为油质量的0.8%,离子液体[BMIm]BF4用量为油质量的1.5%,此条件下绝缘油产率为84.6%。对净化后合成的植物绝缘油进行了理化、电气性能的测试,结果表明:植物绝缘油闪点大于170℃,工频击穿电压达到64kV,90℃介损为0.0087,90℃体积电阻率为6.43×1010?·m,相对介电常数εr为3.08,对环境无污染,各项指标均能满足绝缘油的要求,是矿物绝缘油的良好替代品。本文探讨了油酯的氧化机理;分析了抗氧化剂的作用机理,考察了BHT、PG、TBHQ等抗氧化剂的抗氧化性能及其用量,得出结论:三种抗氧化剂中TBHQ的抗氧化效果最佳,抗氧化剂最佳用量为50ppm。更多还原

【Abstract】 Mineral insulating oil has extensive application in oil-immersed voltage equipment. It has excellent electric insulating property, high coolant capability and low cost. However, it is poorly biodegradable as well and may contaminate soil, waterways, and resident conditions when serious oil spill or leakage occurs. It can’t achieve the request of environmental protection. Therefore, research on the environment-friendly vegetable insulating oil has become a pop project.Researches on using vegetable oil as dielectric liquid began at the same time as mineral oil. Because of its weak antioxygenic property and high viscosity, vegetable oil was restricted in capacitor impregnan. From 1990s, the researches of using vegetable oil as dielectric liquid have been developed again. Vegetable oil, extracted from crude seed oil, is fully biodegradable. Nowaday, the reserves of mineral oil became decreased, so vegetable oil could be the green substitute as mineral oil.The rapid method of preparation of insulating oil was studied with rapeseed oil and methanol catalyzed with ionic liquid under microwave irradiation. Factors influencing on yield of insulating oil were investigated following microwave power, microwave irradiation time, dosage and type of ionic liquid, amount and type of catalyst and mass ratio of methanol to oil. The results show that, microwave and ionic liquid had synergetic effect on transesterification when using NaOH as catalyst. Ionic liquid has the effects of catalysis and solubilization, which can eliminate the interface of methanol and oil, and it also can reduce the saponification and improves efficiency of transesterification. Microwave can also improve the transesterification efficiency for its thermal and non-thermal effect. The optimum conditions for preparation insulating oil are as follows: microwave power 1000W, reaction time 10min, reaction temperature 65℃, molar ratio of methanol to oil 6:1, dosage of catalyst 0.8% (mass ratio of NaOH to oil),dosage of ionic liquid 1.5% (mass ratio of [BMIm]BF4 to oil). The yield of insulating oil is 84.6%.The physical and chemical properties, also electric performances of the vegetable insulating oil after microwave-assisted synthesis is tested. The results show that, the flashpoint of the insulating vegetagble oil is higher than 170℃, the dielectric breakdown voltage can reach as high as above 64 kV/2.5 cm, the dissipation factor at 90℃is 0.0087, the volume resistivity at 90℃is 6.43×1010?·m, the high dielectric constant dielectricεr is 3.08, pollution-free to environment, every index can meet well with the requirement for the insulating oil, so it is a excellent substitute of mineral insulating oil.The oxidation mechanism of oil was discussed and the action mechanism of antioxidants was analyzed. Different kinds of antioxidant such as BHT, PG, TBHQ are tested in this study. It is found that the most suitable antioxidant is TBHQ and the optinal dosage for transgenic rapeseed oil is 50ppm.更多还原