Browsing by Author "Onuh, Emmanuel Idoko."

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Combustion studies of biodiesel fuel from moringa, jatropha and restaurant oil.
(2016) Onuh, Emmanuel Idoko.; Inambao, Freddie Liswaniso.
Biodiesel is a renewable alternative to finite diesel and, has the capacity to reduce emission and broaden energy access particularly in sub-Saharan Africa where economic growth has been, to some extent, constrained by global warming and a lack of universal access to sustainable source of energy. In the transport sector, a niche exist for biodiesel derived from non-edible feedstock such as waste oil, jatropha and moringa in sub-Saharan Africa. Extraction of oil from jatopha and moringa were achieved via manual as well as soxhlet method using normal hexane, petroleum ether and distilled gasoline. A numerical property prediction scheme was implemented (and validated with experimental data) to obtain the thermo- physical as well as the transport properties of the resulting fuel for the various samples. This prediction scheme reduced the number of experimentation for property determination from nine to one per sample. The pure fuel samples were evaluated in a 3.5kw diesel engine to determine their performance and emissions. The Brake Specific (BS in g/kWh) emissions across the full load spectrum were benchmarked against the United State Environmental Protection Agency (US, EPA) and the European Union (EU) emission caps. This study is a follow-up to an earlier work by Eloka Eboka which focused on the determination of optimal production process for biodiesel using different technique and catalyst. In that work, the engine test was a qualitative evaluation of different mixture ratio forming new hybrids and the engine test protocol did not follow the ISO 8178-4:2006 test cycle categorization nor was the emission benchmarked against the EPA/EU emission caps (both of which were implemented in this study). The extraction results not only confirmed normal hexane solvent and soxhlet method as the optimal means of extraction (with a 37.1% and 51.8% yield for moringa and jatropha respectively) but, gave hint of the potential of distilled Gasoline as a viable solvent (with a 40.2% and 34.1% yield for moringa and jatropha respectively). The validated numerical prediction scheme reduce research cost and time without compromising accuracy. The performance and emission revealed that the Brake specific fuel consumption (BSFC) and brake thermal efficiencies for both diesel and the biodiesels only differ marginally (±4% and ±5 respectively at peak load). Carbon monoxide (CO), unburnt hydrocarbon (UHC) and particulate matter (PM) emissions (in part per million-ppm) showed decreasing trend with load increase and were lower than those of diesel. Oxides of nitrogen (NOX) emission for the biodiesel were lower than those of diesel. The Brake Specific (BS) emission results in comparison to the EU and EPA regulation showed various level of compliance and non-compliance to the emission limits. The result also showed that samples with higher proportion of unsaturated FAME have poorer engine performance and results in higher unwanted emission than saturated FAME. In broad terms, engine retrofitting and novel design could effectively bridge the performance and emission gaps observed between diesel and biodiesel. A multi-blend (saturated and unsaturated FAME) and multi-strategy (Modular kinetic and premix/DI) was recommended as a remediation strategy. For numerical prediction purpose, a 3D CFD with multi zone and detailed chemistryusing KIVA-3V code was proposed.
Numerical and experimental investigations of optimal fatty acid methyl ester hybrid for enhanced engine performance and emission mitigation in the conventional compression ignition strategy.
(2020) Awogbemi, Omojola.; Inambao, Freddie Liswaniso.; Onuh, Emmanuel Idoko.
The utilization of petroleum-based diesel fuel to power compression ignition (CI) engines has been hampered by inefficient combustion process resulting in unsatisfactory engine performance and emission of hazardous gases. Fatty acid methyl ester (FAME), due to its renewability, biodegradability, and environmentally friendly emissions, has been acknowledged as a viable alternative fuel for CI engines. The application of waste cooking oil (WCO) as feedstock for FAME production did not conflict with food chain, guarantees appropriate disposal of used vegetable oil, and prevents contamination of aquatic and terrestrial habitats. The FAME was produced by transesterification of WCO samples collected from restaurants, catalyzed by calcium oxide derived from chicken eggshell waste powder subjected to high temperature calcination. Properties and fatty acid (FA) composition of the FAME were determined, the fuel used to power an unmodified CI engine, and measure the performance and emission characteristics experimentally. Numerical techniques, including, matrix laboratory, response surface methodology, Taguchi orthogonal, artificial neural network, and multiple linear regression were utilized to unearth the optimal FAME candidate, determine the properties, FA composition, performance and emission characteristics of the newly generated FAME and were found to agree with experimental results. It was discovered that FAME candidate with a concentration of palmitic acid of 36.4 % and oleic acid of 59.8 % produced improved brake thermal efficiency and brake mean effective pressure as well as reduced fuel consumption, and other regulated emissions.
Studying the feasibility of hydroprocessing used cooking oil into hydrogenation derived renewable diesel from local feedstock and catalyst.
(2021) Pelemo, Josiah.; Inambao, Freddie Liswaniso.; Onuh, Emmanuel Idoko.
Identifying and developing heterogeneous catalysts capable of mild-cracking used cooking oil (UCO) into hydrogenation-derived renewable diesel (HDRD) or green diesel production has posed a considerable challenge to commercialization of this fuel type in the energy sector. HDRD has received wide acceptance as alternative renewable energy that guarantees a pollutant-free environment, sustainability, renewability, and possesses a high degree of compatibility with compression ignition (CI) engine with little or no retrofitting needed. This research focuses on the feasibility of locally sourced UCO and catalysts for hydrogenation into green diesel. The objectives of this research are to produce a biofuel for CI engine using biowaste catalyst and UCO as a feedstock. Various studies have highlighted the benefit of UCO as a feedstock for biofuel production. UCO was collected from takeaway outlets. The samples were prepared by the in-situ hybridization method, heated on an electric heater fitted with a magnetic stirrer kept at 110 ⁰C and agitating speed of 50 rpm. The novel approach of in-situ hybridization of waste cooking oil was investigated. The outcome of the investigation showed that hybridization of the samples caused an increase in iodine value from 80.4 cg/g to 100.2 cg/g, affected kinematic viscosity, saponification value, and density, but did not affect cetane number, higher heating value, and acid value. The results are evidence that hybridization is a viable technique for improving the quality of existing feedstock and creating high-quality feedstock for the production of HDRD. Bio-based thermal power plant fly ash (BBTPPFS) was sourced locally from an ESKOM power plant in South Africa, pulverized, and developed into a fine powder, while SiO2, Al2O3, and CaO were procured from a commercial supplier. The samples were reinforced in various proportions and subjected to thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), and X-ray diffraction (XRD) characterization processes. The results revealed that SiO2 reinforced with BBTPPFS showed adequate properties that render it viable as a potential low-cost green catalyst for hydrogenation and capable of mild cracking to achieve a green diesel range C15-C18. The properties of locally sourced catalyst and feedstock were evaluated; experimental results revealed that the BET surface area, pore-volume, and micropore volume of fly ash reinforced with SIO2 showed high catalytic viability because of its capability to withstand temperatures up to 950 °C. Also, the addition of SIO2 to BBTPPFS showed a significant percentage increment in quartz, calcite, and mullite. This property is further evidence of its viability as a potential local catalyst for hydrogenation. HDRD were produced from hydro-processed used cooking oil using a locally sourced fly ash catalyst. The properties of HDRD were measured according to the ASTM standards and compared with green diesel. In terms of fuel quality, engine performance, and emission outcome, HDRD showed high yield and exhibited excellent fuel properties. The results from the engine test and combustion performance in a diesel engine are compatible with results from a CI engine, and meet acceptable performance and emission standards.