Preparation of biodiesel by short path distillation of rapeseed raw oil and alkaline catalyzing reaction

Biodiesel is an environmentally friendly renewable biomass fuel. Short path distillation was adopted to remove free fatty acids and pigments from rapeseed raw oil followed by transesterification reaction with methanol in the presence of potassium hydroxide to obtain high quality biodiesel. Better transesterification conditions of rapeseed oil were presented by single factor and response surface methodology analysis. Results show that 94% conversion rate of biodiesel is achieved when reaction temperature 60℃, methanol to material ratio 6.3∶1(mol/mol), amount of catalyst 1.01%(m/m) and reaction time 47.5 min. The properties of biodiesel obtained are similar with 0^# diesel. It provides technological conditions for producing biodiesel on a large scale.