Production, evaluation and testing of bioethanol from matooke peels species as an alternative fuel for spark ignition engine: a case study of Uganda.

Abstract

Conversion of new lignocellulose biomass (LCB) waste to energy is an innovative technique for waste valorization and management which reduces environmental pollutions and offers socioeconomic benefits. This has made the LCB to be significant due to its novel behavior towards bioenergy. The aims of this study is to characterize the biomass, evaluate and produce the bioethanol fuels from unique LCB which is matooke peels species, and examined the emissions and combustion effects of low content rates of bioethanol blends with gasoline in a modernized spark-ignition engine. The matooke peels species such as Mbwazirume and Nakyinyika biomass peels, which are pretreated and untreated were characterized to identify its use in bioenergy production. This characterization of biomass was carried out using various analyses such as proximate and ultimate analysis, thermo-gravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometer (EDXS). Experimental findings reveal that the pretreated Mbwazirume biomass exhibits excellent solid fuel properties when compared to untreated Mbwazirume, pretreated and untreated Nakyinyika biomass peels. Bioethanol fuels were produced from Mbwazirume and Nakyinyika biomass peels through a fermentation process using Saccharomyces cerevisiae and analyzed using ANOVA. The study also optimized production variables and determined the models for separate hydrolysis and fermentation (SHF). The properties of the bioethanol were measured according to relevant ASTM standards and compared with the standard ethanol and gasoline. Mbwazirume biomass shows higher bioethanol yields and excellent fuel properties, this serve as a fuel of choice for further experiment. The bioethanol ratios were blend with gasoline at (E0, E5, E10, and E15) used in the development of further experiments on engine and combustion performance, and exhaust emissions test in a modernized TD201 four-stroke petrol engine. The results obtained were computed, modeled, evaluated and analyzed. Results show that the small differences in properties between bioethanol-gasoline blends are enough to create a significant change in the combustion system. These effects lead to behavioral mechanisms which are not easy to analyze or understand, sometimes make it difficult to identify the fundamentals of how blend ratios affect emissions and performance.