Open AccessValorization of a high-acidity residual oil generated in the waste cooking oils recycling industries
Author(s) -
Paloma Álvarez Mateos,
Juan Francisco GarcíaMartín,
F. J. Guerrero-Vacas,
Cristiranjo,
C. C. Barrios-Sánchez,
María del Carmen PérezCamino
Publication year - 2019
Publication title -
grasas y aceites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.384
H-Index - 46
eISSN - 1988-4214
pISSN - 0017-3495
DOI - 10.3989/gya.1179182
Subject(s) - chemistry , biodiesel , transesterification , methanol , fraction (chemistry) , catalysis , hydrolysis , organic chemistry , waste oil , fatty acid methyl ester , triglyceride , pulp and paper industry , vegetable oil , food science , biochemistry , cholesterol , engineering
A sludge fraction is obtained from the industries which recycle cooking oil and this sludge contains a large amount of oil with an extremely high acidity ( > 60%). In this work, we propose a scheme for methyl ester production from this residual oil consisting of the esterification of the free fatty acids followed by the transesterification of the remaining triglycerides. Esterifications were carried out with different methanol:oil molar ratios, and various catalysts in different weight ratios. The results revealed that homogeneous catalysts produced higher yields than heterogeneous ones in the esterification reaction. With the aim of improving the process, a previous triglyceride hydrolysis was assayed using lipases from Candida rugosa. Finally, the 3-stage process was performed under the most favorable conditions for each stage obtaining 84% wt. fatty acid methyl esters, which shows the potential of this residual oil as a source of biodiesel.