Multiresponse optimization of biodiesel obtained from a mixture of soybean oil, beef tallow, and waste cooking oil

Abstract

Biodiesel is considered an alternative fuel that offers socio-environmental advantages over regular diesel from fossil origin. Several feedstocks can produce biodiesel, but animal fat and waste cooking oil (WCO) have become attractive due to their low cost and easy availability. These feedstocks can be mixed with traditional soybean oil to improve biodiesel’s properties, such as oxidation stability and cloud point, which would help comply with the quality parameters required by law. This work aimed to optimize pure biodiesel (B100) production from the mixture of soybean oil, beef tallow, and WCO by the methyl route and homogeneous (basic) catalysis. The simplex-centroid mixture experimental design was used to optimize yield, Induction Period (IP), and Cold Filter Plugging Point (CFPP). The results indicated that the optimum formulation was a mixture containing 50% soybean oil, 33% beef tallow, and 17% WCO. The quality parameters evaluated are within limits established by international legislation; IP of 7.11 h and CFPP of 0 °C. The real values of the R2, p-values, or t-values validate the obtained models.