High oleic sunflower biodiesel: Quality control and different purification methods

Abstract

The objective of the present work is to evaluate the production of biodiesel using ethanol and sunflower oil. The extraction of the sunflower oil was evaluated first. An experimental design was used to estimate the influence of the independent variables grain temperature (25° to 110°C) and expeller rotation (85 to 119rpm) on the crude oil. The best result obtained was 68.38%, achieved with a rotation from 100 to 115rpm, grain temperature ranging from 25° to 30°C and moisture content of around 7%. The next study consisted of transesterification, evaluating the influence of the ethanol, oil molar ratio and the catalyst concentration (sodium methylate) on the ester-rich phase yield. The highest yield was 98.39% obtained with a molar ratio of 9:1 and 3% catalyst. An experiment was then carried out on a small reactor and the biodiesel produced was purified by three different methods: acidified water, silica and distillation. The quality aspects of the purified biodiesel samples were evaluated according to the Brazilian specifications for biodiesel, and distillation was shown to be the best method of purification.