Utilization of Waste Transformer Oil for the Synthesis of Biodiesel and Glyptal

Transformers are the important electrical devices which are used for the transmission of electrical energy in power systems. Transformer oil which is also known as insulating oil provides insulation and cooling to power transformers. During operation it undergoes electrical and mechanical stresses which cause deterioration of the properties of the transformer oil and it is discarded as waste in large amounts. Waste transformer oil (WTO) containing toxic pollutants is hazardous to the environment and other living beings. To overcome this problem, it can be converted into a value-added product. The current study involves chemical treatment of WTO by a well-known alkaline transesterification process. In this process, methanol/butanol is used as an alcohol with KOH and the reaction temperature is maintained at 65 °C for 1 h. After the process biodiesel and glycerol are formed. Further the esterification of WTO is also conducted using sulfuric acid with methanol/butanol and the properties such as specific gravity, kinematic viscosity, and flash point are measured for the comparative study of fuel characteristics of the obtained biodiesel and it was found that the biodiesel TW2B7 has reduced viscosity, Biodiesel TW1B4 shows much improved flash point. The obtained crude glycerol is utilized to produce valuable product glyptal (cross-linked polyester) which is a binding material and also insulating enamel which is used for making paints. The esterification reaction between obtained glycerol and phthalic anhydride in the presence of a catalyst is carried out in a lab-scale batch reactor followed by a sand bath at high temperature. Different proportions of glycerol and phthalic anhydride are used in the preparation of glyptal and the percentage yield was calculated. Thus this paper aims to obtain a biodiesel from WTO and utilize the produced by-product crude glycerol into an alkyd resin.