Effect of waste-fed black soldier fly larvae oil-based biodiesel towards diesel engine fuel delivery metal corrosion and elastomer degradation

This paper aims to determine the effect of black soldier fly larvae (BSFL) oil-based biodiesel (B100) towards metal corrosion and elastomer degradation. Copper (Cu) and nitrile butadiene rubber (NBR) were exposed to BSFL-B100, industrial diesel (D2) and palm oil biodiesel (P-B100) for 1200 h at 25 °C. Corrosion rate, elastomer volume, tensile and hardness change, as well as surface morphology and total acid number (TAN) were determined. Cu had highest corrosion rates in BSFL-B100 at 0.00195 mm/yr, followed by in P-B100 at 0.00163 mm/yr and D2 at 0.00096 mm/yr. NBR exposed to BSFL-B100 had highest volume change by 31.4 % followed with in P-B100 at 29.0 % and finally in D2 at 19.4 %. BSFL-B100 exhibited significantly higher TAN increases than P-B100 and D2 after exposure to both Cu (188 %, 118 % and 84 %) and NBR (233 %, 139 % and 95 %) indicating greater fuel degradation in BSFL-B100, thus adversely affecting Cu corrosion and NBR degradation. Despite key fuel properties of prepared BSFL-B100 were within the limits specified in American Society for Testing and Materials (ASTM) D6751–23 and exhibited materials degradation comparable to P-B100, it however experienced higher fuel degradation measured in terms of TAN than P-B100 under similar experimental conditions. This could be associated to higher polyunsaturated fatty acids present in BSFL-B100 than P-B100 which is susceptible to oxidation which could adversely affect materials degradation.