PERFORMANCE EVALUATION OF METHYL ESTER PREPARED FROM COTTONSEED OIL.

AUTHOR: UDE, CALLISTUS NONSO

DEPARTMENT: CHEMICAL ENGINEERING

AFFILIATION: NNAMDI AZIKIWE UNIVERSITY, AWKA

The purpose of this work was to produce biodiesel from refined cottonseed oil by alkali transesterification with methanol using different conditions and focusing on; characterization of the oil, determination of the fuel properties, kinetics and thermodynamics, optimization of the process parameters using RSM, engine performance testing and prediction of model for the performance using Artificial Neural Network (ANN). The parameters investigated were the reaction time (1, 2, 3, 4 and 5 hours), catalysts concentration (2, 4, 6, 8, 10, and 12 % wt), methanol/oil molar ratio (4:1, 6:1, 8:1, 10:1, 12:1 and 14:1), reaction temperature (25, 45, 65, 75 and 85oC) and agitation speed (150, 200, 250, 300 and 350rpm). The physical and chemical properties of the oil and biodiesel were determined in order to investigate the effects of the properties of the triglyceride and the reaction parameters on the product characteristics, yields and purity. The process parameters were optimized using Response Surface Methodology (RSM) in combination with Central Composite Design, CCD and the engine performance was carried out using a steady-state diesel engine test bed. Some of the experimental data was used to train and develop ANN model based on optimization algorithm for the engine performance. Multi layer perception network (MLP) was used for non linear mapping between the input and the output parameters. Different activation functions and several rules were used to assess the percentage error between the desired and the predicted. The properties of the cottonseed oil determined had decisive effect on the physical and chemical properties of the methyl esters. The studied reaction conditions did not significantly affect the properties of the biodiesel but affected the yield. The yield increased as the process parameters increased and decreased when the process parameters were above the optimal. The biodiesel produced generally met the criteria required for commercial biodiesel. The Response Surface Methodology (RSM) studies allowed the development of a second order model representing the influence of the reaction conditions on the biodiesel yield. The optimum reaction conditions were; reaction time of 4h, catalyst concentration of 6 wt% (CaO) and 8wt% (MgO), reaction temperature of 65oC, methanol/oil molar ratio 6:1 (CaO) and 8:1 (MgO) and agitation speed of 250rpm. The optimal yield of 86.6% and 73.3% were obtained for CaO and MgO respectively. The developed kinetics model suggested a second order reaction with activation energies of 57.7KJ/mol (CaO) and 58.2KJ/mol (MgO). The thermodynamics parameters determined showed that the reaction is spontaneous and feasible. The thermal efficiency and brake power of biodiesel blends especially B20 were almost similar to conventional diesel fuel. It was observed that the ANN model can predict the engine performance quite well with correlation coefficient (R) of 0.9743, 0.99137 and 0.97889 for engine brake power, brake specific fuel consumption and brake thermal efficiency respectively. The results exhibited the potential of CaO and MgO in catalysis of transesterification reaction. 

TO VIEW THE FULL CONTENT OF THIS DOCUMENT, PLEASE VISIT THE UNIZIK LIBRARY WEBSITE USING THIS LINK, http://naulibrary.org/dglibrary/admin/book_directory/Thesis/11674.pdf

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