Article info.

ABSTRACT

Received 08 Jul 2018
Revised 22 Sep 2018

Accepted 30 Jul 2019

One of the major technical issues facing biodiesel is its susceptibility to oxidation which is due to its content of unsaturated fatty acid chains, especially those with bis–allylic methylene moieties. In addition,   the presence of air and other factors also influences the oxidation process of biodiesel including presence of light, elevated temperature, as well as extraneous materials such as metals which may be even present in the container material. The overall objective of this work is to evaluate the oxidation stability of Jatropha biodiesel/diesel blends. An acid–catalyzed pretreatment followed by a standard transesterification procedure in a potassium methoxide solution to produce Jatropha methyl ester (JME) from Jatropha curcas L. oil (JO) with high acid value of 16.25 mg KOH/g was accomplished. The analysis of the physicochemical properties showed JME demonstrated potential as a good candidate for feedstock in biodiesel production because the studied physicochemical properties of JME adequately satisfied the relevant standards for biodiesel quality, with the exception of the kinematic viscosity at 40^oC. Also, gas chromatography–mass spectrometry analytical result showed that fatty acid composition of JO was quite similar to that of conventional oils. Especially, the evaluation of oxidation stability of Jatropha biodiesel/diesel blends was accomplished with respect to the change in the quality after oxidation by bubbling oxygen at elevated temperature as well as oxidation of blend fuels in contact with copper plate. The results demonstrated a strong correlation between biodiesel concentration and blend stability; i.e., the increase in biodiesel concentration results in the lower stability in both cases of the copper strip corrosion test and the accelerated oxidation.

Keywords

Biodiesel, blend, FAME, JME, JO, transesterification

Cited as: Dat, N.V., Hirotsu, T. and Goto, S., 2019. Evaluation of the oxidation stability of jatropha biodiesel/diesel blends. Can Tho University Journal of Science. 11(2): 61-68.