Transesterification of Jatropha curcas L. oil using microwave radiation

• Main Authors: Chan, Belinda Almira, Chua, Lester Adriane, Eliseeff, Michael Brian
• Format: text
• Language: English
• Published: Animo Repository 2009
• Subjects: Jatropha; Oilseed plants > Research; Field crops > Research; Microwave heating; Chemical reactions
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/8064
• Institution: De La Salle University

Inedible vegetable oils such as Jatropha curcas L. can serve as an alternative source to avoid scarcity or competition with products intended for human consumption. Studies regarding the feasibility of producing biodiesel from Jatropha curcas L. have been conducted by different agencies such as the Department of Science and Technology. The purpose of this research was to investigate how effective microwave heating is in reducing reaction time and increasing biodiesel conversion in comparison to conventional heating in the transesterification process of crude Jatropha oil using different combinations of various parameters such as reaction time, reaction temperature, oil to alcohol molar ratio and percent weight of catalyst. Fatty acid content of the crude oil must first be lowered before proceeding to the main process. Hence, acid pretreatment was employed using microwave irradiation as the heat source. Various alcohol to oil weight ratios were investigated with other parameters such as reaction time, reaction temperature, catalyst type and amount were held constant. As a result, double acid pretreatment was done using 0.6 alcohol to oil weigh ratio, 5 minutes reaction time, 50C and 1% (w/w) of oil to sulfuric acid catalyst. The range of percent FFA achieved was 0.139%-0.9%. For the transesterification process, the highest conversion attained was 99.1%. The set of parameters used to produce the sample were 1:9 oil to alcohol molar ratio, 1% sodium hydroxide catalyst (w/w of oil), 60C and 7 minutes reaction time. It was observed that the more significant parameters affecting conversion were the oil to alcohol molar ratio and percent weight of catalyst, which were 1:9 and 1% respectively. Hence, the average conversion of the samples obtained using these two parameters were 98.34% with a standard deviation of 0.71. An increase in product conversion, from 90% to 99.1%, was achieved with a significant decrease in reaction time from 2 hours to 7 minutes. Results showed the effectivity of microwave irradiation on the transesterification process in comparison to conventional heating in the study of Hirata S. et al. The physical properties of the biodiesel product were tested and results showed that the density was 0.8889kg/, well within the range of 0.86-0.90 kg/L standard. The flash point was 133ºC - within the standard value of temperature greater than 100ºC. However, the product had high kinematic viscosity which was 6.5 centistokes. Emulsions, which increase biodiesel viscosity, formed since catalyst and free fatty acids were not removed from the biodiesel phase. In the study of Lu, H. et al. on the production of biodiesel from Jatropha oil, a kinematic viscosity of 4.06 centistokes of the washed product was reported, showing the significance of the washing step.