How biodiesel is produced
The biodiesel production process starts when the vegetable oil reaches the biodiesel plant in tanker trucks. It is unloaded and piped to storage tanks, from where it is taken to the pretreatment section. Here any fatty acids, phospholipids and waxes in the oil are removed until refined oil is obtained.
This refined oil passes to the transesterification building; there the oil it reacts with methanol in the presence of a catalyst to become methyl ester, with glycerol lye as a by-product of the process.
The methyl ester is washed to remove any remains of methanol, glycerin, catalyst, etc. and then it is dried until biodiesel is obtained.
The glycerol lye is put into a distillation column where the methanol is recovered through evaporation. It is then recirculated to the start of the process and two further stages are produced: pre-cleaning through evaporation to obtain 90% glycerin, and distillation and bleaching of the glycerin using activated carbon, which gives pharmaceutical quality glycerin (99%).