Production and Characterization of Biodiesel by Hybridization of Moringa stenopetala and Azadirachta indica Seed Oil
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Date
2021-07
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Addis Ababa University
Abstract
Biodiesel (Fatty acid alkyl ester) has been regarded as cleaner, alternative, renewable, biodegradable and environmentally benign energy source. It can replace petrol-diesel and solve challenges accompanied with environmental pollution, climate change, socio-economic, energy crisis and global warming. The aim of this study was production and characterization of biodiesel by hybridization of M. stenopetala and A. indica seed oil to substitute conventional diesel fuel with greener, alternative and eco-friendly energy source. The statistical software package Design-Expert® Response Surface Method (RSM), Box-Behnken Design (BBD) method, was employed in experimental design and result analysis. The considered factors of the study were: Oil mixing composition, Catalyst dose and Reaction time with three levels for each factor, low (-1), medium (0) and high (+1); and the other operational parameters, alcohol to oil molar ratio, temperature and mixing speed, were kept constant. The interaction effects of factors and their influences on response were studied. The considered oil hybrid compositions subjected to the transesterification reaction were: M25N75 (25%v/v M. stenopetala seed oil : 75%v/v A. indica seed oil), M50N50 (50%v/v M. stenopetala seed oil : 50%v/v A. indica seed oil) and M75N25 (75%v/v M. stenopetala seed oil : 25%v/v A. indica seed oil) with their corresponding biodiesel, BM25N75, BM50N50, BM75N25; catalyst dose of 1 %w/v, 1.5 %w/v and 2 %w/v; and reaction time of 20 min, 40 min and 60 min. A total of 15 number of runs were conducted with 3 levels for each numeric factors. The quadratic model was developed for conducted experiment with statistical significance, P - value < 0.0001. The analysis of variance (ANOVA) and coefficients of determinations were used to evaluate the quality of the model, where the main comparison was conducted at 5% LSD. The model adequacy was expressed using, R2 = 0.9933, Adj- R2 = 0.9812, Pred- R2 = 0.8993 and lack of fit test with P - value = 0.1071 (statistically not significant). The value of Pred- R2 = 0.8993 was adequately in agreement with the value of R2 = 0.9933, showed that the developed quadratic model equation can be used to navigate the design space. The optimum, 91.72% biodiesel yield was obtained at oil mixing composition (57.17 %v/v of M. stenopetala and 42.83 %v/v of A. indica seed oil), catalyst dose (1.88 %w/v KOH) and reaction time (60 min). The evaluation of FTIR and physicochemical characteristics were conducted for the optimized product according to ASTM and EN 14214 standard test methods; and the obtained results were in agreement with the standard limit of biodiesel quality.
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Keywords
Azadirachta indica,, Biodiesel, Catalyst, Hybridization, Methanol, Moringa stenopetala, n- Hexane, Transesterification