The transesterification of rapeseed and waste sunflower oils: Mass-transfer and kinetics in a laboratory batch reactor and in an industrial-scale reactor/separator setup.
We have investigated the transesterification of rapeseed (RO) and waste sunflower (SO) oils with methanol in the presence of potassium hydroxide as a catalyst. The transesterification of tri-acylglycerols was first conducted in a batch reactor. The effect of the temperature on the reaction rates was studied at a constant molar ratio of the alcohol to tri-acylglycerols (6:1) and for a constant concentration of the catalyst (1.0wt%). Size-exclusion chromatography and (1)H NMR spectroscopy were used to quantitatively monitor the transesterification reaction. The mass-transfer coefficients of the tri-acylglycerols during the initial transesterification stage were found to be 0.2-1.2x10(-5)mmin(-1), depending on the type of oil and the temperature. Calculated activation energies implied that at higher temperatures the formation of mono-acylglycerols and glycerole was favored for the SO (93kJ/mol for the forward and 48kJ/mol for the backward reaction) and the RO (47kJ/mol for the forward and 36kJ/mol for the backward reaction), respectively. For the continuous industrial reactor/separator setup, the optimum methanol recycle ratio was established as 0.0550.
Klofutar
B
B
ZORD Slovenija, 1000 Ljubljana, Slovenia. b.klofutar@zord.org
Golob
J
J
Likozar
B
B
Klofutar
C
C
Zagar
E
E
Poljansek
I
I
D002850:Chromatography, Gel; D004951:Esterification; D005229:Fatty Acids, Monounsaturated; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D010938:Plant Oils / Q000737:chemistry*; D000074262:Rapeseed Oil; D000074242:Sunflower Oil
D005229:Fatty Acids, Monounsaturated; D010938:Plant Oils; D000074262:Rapeseed Oil; D000074242:Sunflower Oil