Environment-Congenial Biodiesel Production from Non-Edible Neem Oil

Abstract

In developing countries like India, where edible oils are in short supply, the contribution of non-edible oils like neem as a source for biodiesel production will be of great importance in the coming days. Biodiesel was produced from non-edible neem oil having a free fatty acid content of 19% in a two-step process, as free fatty acid of more than 1% in the feedstock adversely affects the single step alkali catalyzed transesterification process by soap formation. The first step of acid catalysed esterification reduced the free fatty acid content of neem oil to below 1%. The optimum combinations of parameters for pretreatment were found to be 0.60 volume by volume (v/v) methanol-to-oil ratio, 1% v/v H2SO4 acid catalyst and 1 hr reaction time. The next base catalysed transesterification process converted the pretreated oil to neem biodiesel. The optimum combination of parameters for transesterification was found to be 0.24 v/v methanolto-oil ratio, 1.08% weight by volume (w/v) catalyst concentration and 34 min reaction time. This two-step process gave an average yield of 90%. The fuel properties of neem biodiesel were found to be comparable to those of diesel, and conform to the latest American Standards for Testing of Materials Standards.