Document Type
Article
Publication Date
1-1-2015
Abstract
The influence of sonoluminescence transesterification on biodiesel physicochemical properties was investigated and the results were compared to those of traditional mechanical stirring. This study was conducted to identify the mechanistic features of ultra sonication by coupling statistical analysis of the experiments into the simulation of cavitation bubble. Different combinations of operational variables were employed for alkali-catalysis transesterification of palm oil. The experimental results showed that transesterification with ultrasound irradiation could change the biodiesel density by about 0.3 kg/m(3); the viscosity by 0.12 mm(2)/s; the pour point by about 1-2 degrees C and the flash point by 5 degrees C compared to the traditional method. Furthermore, 93.84 of yield with alcohol to oil molar ratio of 6:1 could be achieved through ultrasound assisted transesterification within only 20 min. However, only 89.09 of reaction yield was obtained by traditional macro mixing/heating under the same condition. Based on the simulated oscillation velocity value, the cavitation phenomenon significantly contributed to generation of fine micro emulsion and was able to overcome mass transfer restriction. It was found that the sonoluminescence bubbles reached the temperature of 758-713 K, pressure of 235.5-159.55 bar, oscillation velocity of 3.5-6.5 cm/s, and equilibrium radius of 17.9-13.7 times greater than its initial size under the ambient temperature of 50-64 degrees C at the moment of collapse. This showed that the sonoluminescence bubbles were in the condition in which the decomposition phenomena were activated and the reaction rate was accelerated together with a change in the biodiesel properties. (C) 2014 Elsevier B.V. All rights reserved.
Keywords
Biodiesel, Ultrasound, Transesterification, Mechanical stirring, Biodiesel properties, Cavitaion
Divisions
fac_eng
Funders
University of Malaya High Impact Research Grant from the Ministry of Higher Education HIR-MOHE-D000038-16001,Bright Spark Unit (from University of Malaya, Malaysia)
Publication Title
Ultrasonics Sonochemistry
Volume
22
Additional Information
Sajjadi, Baharak Abdul Aziz, A R Ibrahim, Shaliza eng Research Support, Non-U.S. Gov't Netherlands 2014/07/02 06:00 Ultrason Sonochem. 2015 Jan;22:463-73. doi: 10.1016/j.ultsonch.2014.06.004. Epub 2014 Jun 20.