Faculty Publications
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Item Microwave-assisted batch synthesis of Pongamia biodiesel(2010) Venkatesh Kamath, H.; Iyyaswami, I.; Saidutta, M.B.Background: The major bottleneck of biodiesel synthesis is its cost and this is mainly attributed to the feedstock material. Pongamia pinnata oil is a nonedible oil that is available in plenty in India and has negligible applications. Several methods of synthesis have been established, each having their own advantages and disadvantages. Results & discussion: Biodiesel from high-free fatty acid, nonedible, Pongamia oil was synthesized under microwave irradiation with single- and two-step methods. Experimental investigations showed that although the single-step method had a high yield (80%), the acid value of biodiesel was quite high. Hence, the two-step method seems to be a better approach as it yielded 90%, with 1:10 oil:methanol molar ratio and 1 wt% KOH. Along with a decrease in the reaction time to 4-5 min, separation time was also decreased by at least 90%. A conventional heating method was employed to compare the effects of microwave irradiation on biodiesel synthesis. Conclusion: The results indicate significant improvement in the yield, reaction time and processing time of biodiesel under microwave irradiation. The synthesis of Pongamia biodiesel under microwave irradiation could perhaps lead to cost effective and faster technology in countries such as India. © 2010 Future Science Ltd.Item Optimization of two step karanja biodiesel synthesis under microwave irradiation(2011) Venkatesh Kamath, H.; Iyyaswami, I.; Saidutta, M.B.The free fatty acid of crude karanja oil (Pongamia pinnata) was reduced and biodiesel was synthesized from pretreated oil under microwave irradiation. The process variables such as irradiation time, methanol-oil ratio and sulfuric acid concentration for pretreatment step; irradiation time, methanol-oil ratio and KOH concentration were optimized through the Box-Behnken experimental design. The free fatty acid of crude karanja oil was reduced to 1.11 ± 0.07% with an optimal combination of 190 s irradiation time (180 W), 33.83 (w/w)% methanol-oil ratio and 3.73 (w/w)% sulfuric acid concentration. An optimal combination of 150 s irradiation time, 33.4 (w/w)% methanol-oil ratio and 1.33 (w/w)% KOH concentration yielded 89.9 ± 0.3% biodiesel. The model was validated by conducting experiments at optimal design conditions. The present work confirmed that the microwave energy has a significant effect on esterification and transesterification reaction. © 2010 Elsevier B.V. All rights reserved.Item Microwave-assisted pyrolysis of food waste: optimization of fixed carbon content using response surface methodology(Taylor and Francis Ltd., 2021) Kadlimatti, H.M.; Raj Mohan, B.; Saidutta, M.B.Pyrolysis of food waste using microwave irradiation was carried out in this study to produce quality biochar for heating applications. Optimum conditions for microwave-assisted pyrolysis of food waste particles were determined using response surface methodology (RSM). Combined effects of the operating variables, namely pyrolysis temperature (°C), residence time (min) and nitrogen flow rate (mL min?1), were analyzed by conducting 20 experiments. Microwave-assisted pyrolysis results were correlated by applying RSM with the regressions coefficients of 92.90% for biochar and 90.305% for fixed carbon content. Microwave power of 450 W yielded 60.03 wt. % of biochar with a fixed carbon content of 48.71 wt. % under the optimum pyrolysis conditions of 400 °C temperature, 30 min residence time and 50 mL min?1 of nitrogen flow rate. The higher heating value of the biochar was 33.35 MJ kg?1. © 2019 Informa UK Limited, trading as Taylor & Francis Group.