Sustainable Energy Consumption

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Effect of Compacting Pressure on Fuel Properties of Finger Millet Briquettes
(International Institute for Science, Technology and Education (IISTE), 2017-11) Ayub, Hesborn R.
In this work, the effect of compacting pressure on fuel properties of finger millet briquettes was investigated and reported. Four different varieties of finger millet namely P224, Gulu-E, U-15 and Okhale-1 were used to produce briquettes without a binder using manual hydraulic press at predetermined compacting pressure of 15, 25 and 35MPa. The proximate analysis results of the resultant briquettes was between 68-70% volatile matter, 21-24% fixed carbon, 9-11% moisture content and 7-8% ash content which is comparable with those of other biomass materials such as rice, wheat and wood. On the effect of compacting pressure on fuel properties, the study showed an increasing trend in briquette density and compressive strength as compacting pressure increased from 15 to 35MPa. However, as compacting pressure increased, the burning rate decreased due to reduced air voids in the briquettes thus limiting mass and heat transfer during combustion.
Investigating the Effect of Selected Parameters on Moisture Removal Rate of an Experimental Forced Convection Solar Grain Dryer
(Scientific & Academic Publishing, 2018) Osodo, Booker; Nyaanga, Daudi
Although forced convection solar grain dryers achieve greater drying rates than natural convection dryers, optimum air velocity, grain layer thickness and drying air temperatures are necessary for improved performance. Number of trays used also affects performance. This study investigated the moisture removal rate (ratio of mass of moisture removed to mass of wet grain per hour) of a solar grain under different drying conditions. The effect of air velocity, layer thickness, number of trays and temperature on moisture removal rate (MRR) was investigated. MRR increased with increase in both drying air velocity and temperature at constant layer thickness. For 0.02 m thickness, MRR increased from 0.048 to 0.061 kg moisture / (kg wet grain. hour). However this increase was only significant at lower temperatures (below 45°C). Changing from 40 to 45°C caused a significant increase, but increasing temperature above 45°C did not. Also, MRR decreased with increase in layer thickness at constant air velocity. At 0.408 m/s air velocity, as layer thickness increased from 0.02 to 0.08 m, MRR decreased from 0.061 to 0.022 kg moisture / (kg wet grain. hour). Finally, when drying a given layer thickness, use of two trays did not significantly improve MRR.
Optimization of Binary Mixtures of Biodiesel and Fossil Diesel for Clean Energy Combustion
(Springer Nature, 2019-05-31) Mosonik, Bornes C.; Kibet, Joshua K.; Ngari, Silas M.
There is an urgent interest initiated to develop clean energy resources with the aim of reducing exposure to environmental pollutants and explore model fuels that can hasten the achievement of clean energy combustion. This work investigates various ratios of biodiesel and commercial diesel in order to propose model binary fuels for clean energy combustion. Accordingly, diesel blends of ratios 1:1, 3:2 and 2:3 were each pyrolyzed at a contact time of 5 s in a quartz reactor at 1 atmosphere pressure. A model temperature of 500 °C was explored in these experiments. The charcoal content for pure fossil diesel was compared with the binary diesel residue. Gas-phase molecular components were determined using Gas chromatography (GC) coupled to a mass selective detector (MSD). Elemental composition of thermal char was determined using Smart Elemental Analyzer. Radical intensities for the three types of char (biochar, bio-fossil char, and fossil char) were measured using an X-band electron paramagnetic resonance spectrometer. It was noted that at a ratio of 2:3 (Biodiesel: Fossil diesel), harmful molecular products reduced significantly, 76–99%. Elemental analysis data indicated that the carbon content from commercial diesel was very high (≈ 70.61%) as compared to approximately 53% for biodiesel-fossil diesel mixture in the same ratio 2:3. Interestingly, the free radical content was reduced by nearly 50% in favour of the biodiesel/fossil diesel mixture. These results are encouraging and suggest that a better optimized fuel mixture has been found for better clean energy combustion.
Synthesis, characterization and spectroscopic properties of Cu2+:ZnO, Ce3+:ZnO, and Cu2+, Ce3+:ZnO
(Springer Nature, 2020-06-22) Mulwa, Winfred Mueni
Pristine ZnO, Cu2+:ZnO, Ce3+:ZnO and Cu2+, Ce3+:ZnO nanopowders with different doping concentrations (0, 0.31, 0.62, 0.93 and 1.24% of dopant) were synthesized by sol–gel technique with low sintering temperature of 600 °C. The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), UV–Vis optical absorption and photoluminescence (PL) spectroscopy analysis. XRD patterns revealed that all the compounds are hexagonal wurtzite crystalline structure and that all the dopant atoms substituted Zn atoms in the ZnO lattice and there was no formation of extra Phases. SEM photographs displayed morphology of the prepared nanopowders. The UV–Vis absorption spectrum presented an absorption peak at 355 nm which was ascribed to ZnO nanoparticles. The photoluminescence spectrum displayed emission peaks at 486 nm and 527 nm. The 486 nm peak conformed to bandgap excitonic emission and the 527 nm peak was attributed to the existence of independently ionized oxygen vacancies. Sol–gel technique has capability for application in manufacturing units, because its process is simple and the reagents used are economical. Particle sizes in the range 10–51 nm were realized from the TEM analysis.

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