The Making Processes of Natural Ester from Palm Oil through Transesterification Reaction for Transformer Application

It has been more than a hundred year since mineral oil was used as liquid insulation for high voltage transformer. Mineral oil is obtained from petroleum through distillation processes. Petroleum is known as non-renewable resources and non-biodegradable. The flash point of mineral oil is around 150°C, thus it creates a problem for high temperature condition. Based on those facts, a new formula of liquid insulation is needed to replace mineral oil. Natural ester oil is derived from vegetable oil. It is biodegradable, non-toxic, non-flammable, and has a higher breakdown voltage. However, the viscosity of vegetable oil is high so that further treatment is needed in order to reduce the viscosity of the oil. This paper reports a sequential procedure in making natural ester oil through transesterification processes using palm oil for transformer application. The alkyl ester can be obtained from the reaction of triglycerides, alcohol and strong base as a catalyst. The by-product, which is glycerol, is then separated from the oil by using gravitational method as its density is higher than the natural ester oil. In this research, methanol is used as a reactant in transesterification reaction due to its cheap price and its fast reactivity. Potassium hydroxide also has a big role in transesterification, its used as a catalyst to make the process easier.