Environmentally Friendly Production Technology of Biodiesel

Biodiesel usually is produced by transesterification of various vegetable oils or animal fats with methanol. Unfortunately, methanol is highly toxic and harmful to human health. Application of bioethanol instead of methanol would lead to more environmentally friendly production technology which almost completely would be based on renewable resources. Currently in Europe there are no biodiesel producers using ethanol as a raw material, nevertheless FAEE (Fatty Acid Ethyl Esters) is used as biodiesel in Brazil. Mandate to CEN for standards for FAEE for use in diesel engines and heating fuels (M/393) was set in 2006. We established the optimal conditions for synthesis of rapeseed oil ethyl esters (REE) by transesterification of oil with bioethanol produced by distillery "Jaunpagasts Plus" Ltd. from local wheat. The best results were reached, when molar ratio of oil to ethanol was 1:6 and KOH was used as a catalyst (1.5 wt% from the mass of oil). The ethanolic solution of KOH was added to oil in two steps and the reaction was carried out at room temperature (the yield of reaction reached 97 %). We have found out the optimal conditions for production of REE by ultrasonication (24 kHz). It is well known that ultrasonication allows replacing a batch processing with continuous flow processing and it reduces investment and operational costs. The results of our experiments show that duration of reaction can be reduced twice in comparison with the classical method and is 0.5 h. We examined commercially available adsorbent Magnesol for purification of the synthesized biodiesel. The technical parameters of our REE corresponded to requirements of LVS EN 14214 set for biodiesel.