Evaluation of biodiesel from Canarium ovatum (pili) pulp oil and Psophocarpus tetragonolobus (winged bean) seed oil

Biodiesel, or fatty acid methyl esters (FAME) derived from triglycerides of oils of vegetable or animal origin, is an attractive alternative fuel because of its low ecological impact and ease of manufacture. However, some concerns remain about the cost and availability of feedstocks. Studies were conducted on biodiesel derived from two novel sources of oil: the fruit pulp of Canarium ovatum (pili) and the seed of Psophocarpus tetragonolobus (winged bean). Oil was extracted from pili pulp and winged bean seeds using hexane. The pili pulp oil and the winged bean oil were found to have a free fatty acid content of 4.0% and 1.0%, respectively. Thus, a combination of acid-catalyzed esterification and base-catalyzed transesterification was necessary to convert the oils to FAME. Pili pulp FAME was found to have a kinematic viscosity of 4.44 mm 2s-1, a density of 0.887 gmL-1, cloud point of 7 °C, flash point of 155 °C, free glycerol of 0.01%, total glycerol of 0.06%, acid value of 0.31 mg KOH·;g-1, sulfated ash of 0.001%, sulfur of 0.02% and an iodine value of 69 g I2100g-1. Winged bean FAME was found to have a kinematic viscosity of 4.93 mm 2s-1, density of 0.879 gmL-1, cloud point of 29 °C, flash point greater than 160 °C, free glycerol of 0.02%, total glycerol of 0.07%, acid value of 0.26 mg KOH g-1 sulfated ash of 0.001%, sulfur of 0.02% and an iodine value of 82 gl2100g -1. The FAME were found to comply with key standards (ASTM D6751-07, EN14214 and PNS2020:2003) except for the kinematic viscosity of the FAME from winged bean, which was above the maximum limit for the Philippine standard (i. e., PNS2020:2003)