Study of an ethylic biodiesel integrated process: Raw-materials, reaction optimization and purification methods

• An integrated ethylic biodiesel production process was studied.
• Raw-materials, transesterification reaction and purification methods were evaluated.
• The difficulties of ethanolysis are shown and key experimental variables are selected.
• Biodiesel (> 98%) was obtained under optimum conditions using virgin and waste oil.
• Water-free purification methods showed potential but require further optimization.

No studies are reported on ethylic biodiesel integrated processes, considering raw materials, reaction optimization and product purification. The present study aims to: i) select key variables for experimental optimization of ethanolysis using a virgin vegetable oil; ii) perform an optimization study using a waste oil; and iii) evaluate the effectiveness of water free purification methods. Sunflower oil ethanolysis was conducted at different temperatures (30 – 80 °C), catalyst concentrations (0.3 – 2 wt.%), reaction times (0.5 – 4 h) and ethanol: oil molar ratios (2:1 – 12:1). Optimization experiments on waste oil ethanolysis were performed at different temperatures (30 – 50 °C) and ethanol: oil molar ratios (6:1 – 12:1), during 1 h and using 1 wt.% catalyst. Quality parameters were measured according to EN 14214. A cation-exchange resin and a ceramic membrane were evaluated for water-free purification. Regarding sunflower oil ethanolysis, when successful, conversion ranged from 75.2 to 97.7 wt.%. Using both oils under optimized conditions (45 °C, 6:1 ethanol:oil molar ratio), a product with a very high purity (> 98.0 wt.%) was obtained after water washing purification. The 0.1 μm ceramic membrane was more effective than the cation-exchange resin, but it was not possible to obtain a good quality product using both methods.