Effects of antioxidants on oxidation and storage stability of Croton megalocarpus biodiesel

W O Osawa,F J Mulaa,J M Onyari,P K Sahoo

doi:10.1007/s40095-015-0191-z

W O Osawa, F J Mulaa + Show 2 more

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https://doi.org/10.1007/s40095-015-0191-z

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Abstract

The effects of antioxidants and storage on oxidation stability of croton biodiesel and its blends with petro-diesel were determined using PetroOxy equipment. The biodiesel and blends were kept in Pyrex reagent bottles and stored in a metallic locker at room temperature for 8 weeks, a condition that imitated ordinary storage environment in tanks before use. The oxidation stability indices of the biodiesel and blends were determined by measuring Rancimat induction periods for 8 weeks at intervals of 2 weeks. Although the Rancimat induction period for freshly prepared biodiesel of 4 h was higher than the commonly used American standard (ASTM D6751) limit of 3 h, it was lower than the European standard (EN 14214) of 6 h. The induction periods of B50 and lower blends were, however, equal to or greater than 6 h. The Rancimat induction periods for biodiesel with 100 ppm antioxidants were 5.6, 6.8 and 7.8 h for Butylated hydroxyanisol (BHA), Propyl gallate (PRG) and Pyrogallol (PYG), respectively, while the Rancimat induction periods for biodiesel with 1000 ppm antioxidants were 6.8, 8.2 and 10 h for BHA, PRG and PYG, respectively. The oxidation stability index for neat biodiesel decreased by 45 % while that for biodiesel with 1000 ppm antioxidants depreciated by 16, 12.2 and 20.59 % for PYG, PRG and BHA, respectively, during the 8-week storage period. A more rapid decline in oxidation stability was observed in the biodiesel and blends without antioxidants than those with antioxidants. The results from this study showed that the use of appropriate concentrations of suitable antioxidants can greatly improve the oxidation stability of biodiesel and blends which can therefore be stored over longer periods of time before use without undergoing extensive and deleterious oxidative deterioration.

Highlights

The concept of using biofuels in internal combustion engines was established by the inventor of diesel engine, Rudolf Diesel who showed that peanut oil could be effectively used in a diesel engine at an exhibition in Paris in 1900
The results from this study showed that the use of appropriate concentrations of suitable antioxidants can greatly improve the oxidation stability of biodiesel and blends which can be stored over longer periods of time before use without undergoing extensive and deleterious oxidative deterioration
The analytical grade commercial antioxidants, Pyrogallol (PYG), Propyl gallate (PRG), Butylated hydroxyanisol (BHA), Butylated hydroxytoluene (BHT) and tert-Butylhydroquinone (TBHQ) from Merck Chemicals used in this study were supplied by HV Technologies

Summary

Introduction

The concept of using biofuels in internal combustion engines was established by the inventor of diesel engine, Rudolf Diesel who showed that peanut oil could be effectively used in a diesel engine at an exhibition in Paris in 1900. Due to adequate supply and lower cost of petro-diesel at that time, no substantial research activities were conducted on biofuels [1]. The ever-escalating fossil fuel costs and strict world guidelines on exhaust emissions have enhanced the need for substitution of fossil fuels with less polluting and readily available renewable fuels for internal combustion engines [2]. Biodiesel has become very crucial owing to higher demand on existing petroleum reserves and lower hazardous emissions as compared to petroleum diesel-fuelled engines [4]. Biodiesel prepared from low-cost non-edible oils, restaurant waste and animal fats can provide substitute fuel that is technically and environmentally acceptable and economically competitive [5]. Biodiesel-fuelled engines are less polluting than petro-diesel, biodiesel readily undergoes oxidation. Biodiesel dealers are concerned that it may form sediment during storage while equipment operators fear that sediment and gum may form during use and cause engine damage [7]

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