Recovery of side streams in biodiesel production process

Biodiesel is a cleaner burning diesel alternate fuel produced from lipid feedstocks through the transesterification process with alcohol and catalyst. In this study, high free fatty acid Jatropha curcas oil was pretreated using sulfuric acid and methanol. The pretreated oil was transesterified with methanol (6:1) and sodium hydroxide solution at 60 °C for 2 h. The yield of biodiesel was 96%. The recoverable methanol from biodiesel and glycerol was measured as 2.61% and 21.5%, respectively. The permissible limit of methanol in biodiesel is 0.2 wt%. A reactor was developed for the methanol recovery from biodiesel and glycerol. The recovered methanol was 2.3% and 27.38% in biodiesel and glycerol, respectively. After the recovery the biodiesel had 0.154 wt% methanol, which is less than the limit prescribed by ASTM standards. The methanol recovered glycerol was purified at vacuum conditions to produce pure glycerol. Thus the recovery of methanol from biodiesel and glycerol improved the quality of fuel, reduced the production cost through Recycling of methanol and value addition to glycerol.