Decomposition Kinetics of Natural Ester and Mineral oil from Thermogravimetric Analyses

Abstract

With growing environmental concerns, biodegradable insulating fluids are being investigated as alternatives to petroleum-based mineral insulating oil in power transformers. In order to optimize their use, decomposition studies of these alternative fluids are therefore of ultimate importance. This paper investigates the thermal decomposition kinetics of mineral oil and two vegetable-based ester fluids, using the thermogravimetric analyses. The initial and maximal decomposition temperatures are determined using thermal analyses. In addition, the Arrhenius activation energy is calculated for the fluids under study using the Ozawa-Flynn-Wall iso-conversional method. In addition, TGA studies are extended to mineral and natural ester impregnated paper, with the aim of assessing their impact on the thermal decomposition of insulation paper. It is found that the level of mono-unsaturated acids in esters is important for enhancing the thermal stability. The enhanced thermal stability of the esters has advantageously contributed to the improvement of the thermal performance of the insulation paper