Removal of Free Fatty Acids and Impurities from Palm Oil for Use in Bio-Transformer Oils

Abstract

This research aims to study the removal of free fatty acids (FFA) in palm oil to make it suitable for use as transformer oil using the adsorption method. The adsorbent used in this study is hydrogels of amorphous silica. The experiments were conducted by varying the following conditions: adsorbent modification, adsorbent type, adsorbent dosage, temperature, and adsorption time. The adsorption kinetics and equilibrium were studied. The equation for estimating the required amount of adsorbent at different temperatures was developed. It was found that 3 grams of adsorbent per 100 grams of oil were required to reduce the FFA content from 691.64 to 44.53 ppm at room temperature (30°C) and an adsorption time of 1 hour and 30 minutes. This achieved the desired target of reducing the FFA content to below 50 ppm. The analysis of the chemical composition of each fatty acid before and after adsorption using the HPLC technique showed that each type of FFA, including palmitic acid, stearic acid, oleic acid, linoleic acid, and eicosanoic acid, was significantly reduced. The adsorbent was equally effective in removing each type of FFA. The electrical properties of palm oil before and after adsorption were tested. It was found that the palm oil after adsorption had a breakdown voltage of 50 kV and 61.3 kV at a test gap of 2 mm, and 32.6 kV and 37.3 kV at a test gap of 1 mm, respectively. This shows that the reduction in FFA resulted in an increase in the breakdown voltage. This increase makes the use of palm oil as a liquid insulation in transformers more efficient and safer.