Process optimization for production of biodiesel from croton oil using two-stage process

Abstract

Croton oil was extracted from dry seeds by a mechanical pressing machine then filtered to remove solid impurities. Biodiesel was prepared from the oil through a two-stage process in a biodiesel reactor. The optimum reaction conditions were determined by varying parameters such as temperature, oil:methanol ratio and amount of catalysts used. The optimum conditions established in this study were temperatures of 50oC and 60oC for esterification and transesterification respectively, methanol:oil ratio of 3:1 and 6:1 for esterification and transesterification respectively and a base catalyst mass of 1% (w/w) of the oil for transesterification. Esterification was done for two hours while transesterification was done for one hour. A maximum yield of 88% biodiesel which had an acid value of 0.336 mg KOH/g, a density of 0.8858 g/cm3 and viscosity of 4.51 cs at 40oC was obtained. The flash point of the biodiesel was greater than 200 oC which made it safer to store and transport as compared to diesel which had a flash point of 65oC. Both the cloud and pour points of the biodiesel were lower than that of petro-diesel, implying that its blends were more suitable for lower temperature operations. All properties of the biodiesel that were tested satisfied the recommended American Society for Testing and Materials (ASTM) values.