Influence of Variables in the Purification Process of Castor Oil Biodiesel

Biodiesel is a fuel alternative to petroleum diesel, usually obtained by transesterification, which is the reaction of vegetable oils or animal fat with a short chain alcohol in the presence of a catalyst. After the reaction, the biodiesel is purified through a washing process for removing impurities. The washing experiments of castor biodiesel were performed according to the complete factorial design 23. The variables studied were: temperature, pH of wash water, and catalyst (NaOH or KOH). The criterion used to define the best process condition was the minimum amount of water needed to wash the biodiesel. Analyzing the effects of the variables and of their interactions in the experimental procedure, the conditions that favored the minimum consumption of wash water was the acidic pH. The temperature and the catalyst type showed negligible significance for the study during the purification of biodiesel castor.