Binary Effect of Tertiary Butylhydroquinone and Butylated Hydroxytoluene Additives with The Addition of Glycerol Monostearate to Improve Oxidative Stability of Palm Oil-Based Biodiesel

Abstract

Biodiesel is a renewable and environmentally friendly alternative to conventional diesel fuel. However, like any fuel, biodiesel is subject to oxidation, which can negatively impact its quality and performance when kept for long-term. The addition of binary antioxidants such as TBHQ:BHT had been proven to improve oxidation stability of biodiesel. Combining surfactant such as GMS into single antioxidant had been proven to solve its insolubility issue. However, the implementation of mixing binary antioxidants and surfactant has not been done yet. Therefore, this research analyzed the effect of single antioxidant, binary antioxidants, and binary antioxidants with GMS (100 ppm) addition into biodiesel and biodiesel blend B35. The effect was observed within 8 weeks storage period. The result showed that B35 did not have any significant impact. While in pure biodiesel samples, B100-bi and B100-bi+GMS had a slight difference in the results of oxidative parameters. B100-bi showed the best result in induction period and kinematic viscosity. Rancimat test showed 170 hours for B100-bi and 168 hours for B100-bi+GMS. While B100-bi+GMS indicated as the best additives in term of acid number, iodine value, and dispersion test. Hence, the addition of surfactant into binary antioxidants showed similar performance with B100-bi but with slightly better solubility.