Faculty Publications
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Item Producing oleaginous organisms using food waste: Challenges and outcomes(Humana Press Inc. humana@humanapr.com, 2019) Singaram, S.; Thalla, A.K.With organic or food waste being one of the main constituents of the total urban waste generated, it not only makes it essential to seek means for its safe disposal but at the same time reiterates the huge potential that lies with the proper utilization of such a widely available resource. Oleaginous microbes that are effective in producing or storing oil would use food waste rich in carbohydrates, lipids, and proteins, and this oil in turn could be an alternative feedstock for the production of biofuels. However, there are few challenges in the process. The various challenges in this process and methods to address them are discussed in the present chapter. © Springer Science+Business Media, LLC, part of Springer Nature 2019.Item Bio-oil from microwave assisted pyrolysis of food waste-optimization using response surface methodology(Elsevier Ltd, 2019) Kadlimatti, H.M.; Raj Mohan, B.; Saidutta, M.B.Municipal solid waste (MSW) contains on an average 40% food waste and needs to be managed in an environment friendly manner. Food wastes have high energy content and offer a good potential feed stock for pyrolysis. Microwave assisted pyrolysis of food waste at different microwave power levels has been carried out in the present study. Maximum bio-oil yield of 30.24 wt.% is obtained under the optimized pyrolysis conditions of 400 °C temperature, 30 min residence time and 50 mL min-1 of nitrogen flow rate at the microwave power of 450 W. The regression model with 95% confidence level resulted in the high value of R2 = 95.4% with R2 adjusted = 91.2% indicates a very good or excellent fit of the data to the model. Main functional groups as detected by the Fourier transform infrared (FTIR) analysis are alcohols, alkenes, aromatic compounds, primary and secondary amines, carboxylic acid, esters and phenols. Oxygenated and non oxygenated compounds, nitrogenated compounds and other compounds such as phosphine, methyl-, propane, 2-fluoro-, (2-hydroxyethyl) trimethylsilyl methyl sulfide, and 1,3-bis(2-hydroxymethyl)urea have been identified by the gas chromatography/mass spectrometry (GC-MS) analysis. The heating value of the bio-oil was 23.94 MJ kg?1. © 2019 Elsevier LtdItem Experimental studies on cyclic variations in a single cylinder diesel engine fuelled with raw biogas by dual mode of operation(Elsevier Ltd, 2020) Jagadish, C.; Gumtapure, V.In this research work, cycle-by-cycle variations of a single cylinder, diesel engine operated with raw biogas is investigated. The biogas used to run the engine is obtained from food waste and as the composition of 88.10%-CH4 + 11.895%-CO2. To study the combustion characteristics, the naturally aspirated diesel engine is converted into dual mode by inducting the biogas into the intake manifold for different proportions from BG20 to BG60 with a step of 10% is mixed with air (i.e. BG60-60% of biogas by mass) respectively. Combustion parameters are measured and recorded by the means of the data acquisition system (DAQ) for 100 combustion cycle. By determining the parameters such as standard deviation, coefficient of variation and return map, the cycle variability is analyzed. From the experimental result, it is observed that as the engine is operated at higher loads and as the biogas is increased from BG20 to BG60 the cyclic variations for maximum cylinder pressure (Pmax) and indicated mean effective pressure (IMEP) increases. Coefficient of variation of Pmax for BG20 and BG40 is lower by 2.3% and 11.98% as compared to diesel. From time return map, BG40 showed good combustion stability and lesser NOx emission compared to diesel. © 2020 Elsevier LtdItem 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.Item Experimental investigation of methane-enriched biogas in a single cylinder diesel engine by the dual fuel mode(Taylor and Francis Ltd., 2022) Chandrashekar, J.; Gumtapure, V.In this experimental work characteristic such as performance, combustion and emission of a single cylinder, four-stroke constant speed, direct injection, water-cooled diesel engine is investigated. The engine is operated by dual fuel mode using methane-enriched biogas (88.10%-CH4 + 11.89%-CO2) obtained from the food waste. Biogas (BG) is inducted into the engine at intake manifold with various mixtures like BG20, BG30 and BG40 mixed with air (i.e. BG40-40% of CH4 by mass respectively) at actual injection timing of 27.5° before top dead centre (bTDC) for different loads. The performance, combustion and emission characteristics of the engine operated by dual fuel mode were experimentally investigated, and compared with respect to diesel. By observing the experimental results, BG40 was optimized on the basis of lesser emissions and improved performance. BG40 showed lesser brake thermal efficiency and higher brake specific energy consumption than BG20 and BG30 for all loads. On the other hand, BG40 showed lower BTE by 15.5% and 15.62% compared to diesel at 3/4th and full load. Whereas the cylinder peak pressure for BG40 is higher than diesel by 5.36% and the net heat release rate is 14.9% higher than the diesel at full load. BG40 emitted higher carbon monoxide (CO) emissions than diesel by 5% at full load. The nitrogen oxide (NOx) emission for BG40 was lesser by 26.60% than diesel at full load, whereas the soot emission was 22.71% lower than diesel at full load respectively. © 2022 Taylor & Francis Group, LLC.Item Experimental Study on the Effect of Injection Timing on a Dual Fuel Diesel Engine Operated With Biogas Derived From Food Waste(American Society of Mechanical Engineers (ASME), 2022) Chandrashekar, J.; Gumtapure, V.The present work emphasizes the effects of injection timing on the characteristics of a 5.2-kW powered four-stroke diesel engine using biogas and its heat loss analysis. The biogas is obtained from food waste consisting of methane (CH4)-88.1% and carbon dioxide (CO2)-11.8% as the composition. The biogas (BG) is selected by mass basis ranging from 20% to 60% with 10% increments and is used to operate the engine by dual-fuel mode. The effect of three injection timings such as 25.5 deg (retarded), 27.5 deg (actual), and 29.5 deg (advanced) before top-dead center (bTDC) under dual-mode operation to enhance the properties of the engine is studied, and the results are compared with diesel mode at actual injection timing. Maximum brake thermal efficiency of 30.1% was observed for BG20 operated at 29.5-deg bTDC injection timing (IT). The dual mode operated at the injection timing of 29.5-deg bTDC showed an increase in cylinder pressure compared to diesel by 11.9% at full load conditions, whereas carbon monoxide emission was lower by 5.2% at 29.5-deg bTDC IT than diesel, and nitrogen oxide emission was lower at 25.5 deg bTDC IT than diesel mode by 45%. Besides, at 75% engine load, the least amount of heat losses was observed for BG50 exhibiting effective conversion of fuel energy into equivalent work higher than that of diesel by 2.2%, respectively. © © 2022 by ASME.