Natural Gas as Transportation Fuel: Solution to National Carbon Dioxide Reduction and Fuel Related Issues in Nigeria

This In this study, strategic substitution of natural gas (NG) as transportation fuel in place of gasoline and diesel has been proposed due to the volume of NG flared on daily basis and its negative impacts on the micro-environment. Data on the volumes of gas flared and quantities of gasoline and diesel distributed from 2000 to 2014 used in this work were sourced from bulletins published by Nigerian National Petroleum Corporation. Empirical formulae and standard conversions were employed to estimate variables (carbon dioxide and cost benefits) based on current price regimes and energy contents of the fuels. The strategic utilization of NG - scenario 1 - (33% to 1% of flared volume) and the baseline (actual situation in 2014) were the two scenarios considered. Findings from this study revealed that at 33% and 1% utilization of flared gas (11.30 x 109 m3), CO2 released were 2.5 x 107 tons and 3.43 x 107 tons, as against 3.46 x 107 (scenario 1) and 3.42 x 107 tons emitted for the baseline scenario, respectively. These values correspond to CO2 reduction of 9.63 x 106 tons (27.79%) and 2.92 x 105 tons (0.84%), for 33% and 1% NG utilization, respectively. Based on energy contents of the fuels, NG as transport fuel is 60.7% and 62.5% cheaper than gasoline and diesel, respectively. The implementation of strategic NG substitution as transportation fuel proposed seems a lasting solution to gas flaring, and petroleum products and their associated problems in Nigeria

Effects of uniform magnetic induction on heat transfer performance of aqueous hybrid ferrofluid in a rectangular cavity

Please read abstract in the article.The National Research Foundation of South Africa under the Renewable and Sustainable Energy Doctoral Scholarships.https://www.elsevier.com/locate/apthermenghj2021Mechanical and Aeronautical Engineerin

Experimental research and development on the natural convection of suspensions of nanoparticles

Suspensions of nanoparticles, widely known as nanofluids, are considered as advanced heat transfer media for thermal management and conversion systems. Research on their convective thermal transport is of paramount importance for their applications in such systems such as heat exchangers and solar collectors. This paper presents experimental research on the natural convection heat transfer performances of nanofluids in di erent geometries from thermal management and conversion perspectives. Experimental results and available experiment-derived correlations for the natural thermal convection of nanofluids are critically analyzed. Other features such as nanofluid preparation, stability evaluation and thermophysical properties of nanofluids that are important for this thermal transfer feature are also briefly reviewed and discussed. Additionally, techniques (active and passive) employed for enhancing the thermo-convection of nanofluids in di erent geometries are highlighted and discussed. Hybrid nanofluids are featured in this work as the newest class of nanofluids, with particular focuses on the thermophysical properties and natural convection heat transfer performance in enclosures. It is demonstrated that there has been a lack of accurate stability evaluation given the inconsistencies of available results on these properties and features of nanofluids. Although nanofluids exhibit enhanced thermophysical properties such as viscosity and thermal conductivity, convective heat transfer coe cients were observed to deteriorate in some cases when nanofluids were used, especially for nanoparticle concentrations of more than 0.1 vol.%. However, there are inconsistencies in the literature results, and the underlying mechanisms are also not yet well-understood despite their great importance for practical applications.The Fundação para a Ciência e Tecnologia (FCT), Portugalhttp://www.mdpi.com/journal/nanomaterialsam2021Mechanical and Aeronautical Engineerin

Experimental investigation on stability, viscosity, and electrical conductivity of water-based hybrid nanofluid of MWCNT-Fe2O3

The superiority of nanofluid over conventional working fluid has been well researched and proven. Newest on the horizon is the hybrid nanofluid currently being examined due to its improved thermal properties. This paper examined the viscosity and electrical conductivity of deionized water (DIW)-based multiwalled carbon nanotube (MWCNT)-Fe2O3 (20:80) nanofluids at temperatures and volume concentrations ranging from 15 ◦C to 55 ◦C and 0.1–1.5%, respectively. The morphology of the suspended hybrid nanofluids was characterized using a transmission electron microscope, and the stability was monitored using visual inspection, UV–visible, and viscosity-checking techniques. With the aid of a viscometer and electrical conductivity meter, the viscosity and electrical conductivity of the hybrid nanofluids were determined, respectively. The MWCNT-Fe2O3/DIW nanofluids were found to be stable and well suspended. Both the electrical conductivity and viscosity of the hybrid nanofluids were augmented with respect to increasing volume concentration. In contrast, the temperature rise was noticed to diminish the viscosity of the nanofluids, but it enhanced electrical conductivity. Maximum increments of 35.7% and 1676.4% were obtained for the viscosity and electrical conductivity of the hybrid nanofluids, respectively, when compared with the base fluid. The obtained results were observed to agree with previous studies in the literature. After fitting the obtained experimental data, high accuracy was achieved with the formulated correlations for estimating the electrical conductivity and viscosity. The examined hybrid nanofluid was noticed to possess a lesser viscosity in comparison with the mono-particle nanofluid of Fe2O3/water, which was good for engineering applications as the pumping power would be reduced.The Fundação para a Ciência e Tecnologia (FCT), Portugalhttp://www.mdpi.com/journal/nanomaterialspm2022Mechanical and Aeronautical Engineerin

Emergence and spread of two SARS-CoV-2 variants of interest in Nigeria.

Identifying the dissemination patterns and impacts of a virus of economic or health importance during a pandemic is crucial, as it informs the public on policies for containment in order to reduce the spread of the virus. In this study, we integrated genomic and travel data to investigate the emergence and spread of the SARS-CoV-2 B.1.1.318 and B.1.525 (Eta) variants of interest in Nigeria and the wider Africa region. By integrating travel data and phylogeographic reconstructions, we find that these two variants that arose during the second wave in Nigeria emerged from within Africa, with the B.1.525 from Nigeria, and then spread to other parts of the world. Data from this study show how regional connectivity of Nigeria drove the spread of these variants of interest to surrounding countries and those connected by air-traffic. Our findings demonstrate the power of genomic analysis when combined with mobility and epidemiological data to identify the drivers of transmission, as bidirectional transmission within and between African nations are grossly underestimated as seen in our import risk index estimates

Investigation into thermal-fluid properties of hybrid ferrofluids as heat transfer fluids

Please read abstract in thesis.Thesis (PhD)--University of Pretoria, 2019.Mechanical and Aeronautical EngineeringPhDUnrestricte

Synthesis and characterization of egusi melon methyl ester as diesel fuel substitute

Biodiesel is a monoalkyl esters of vegetable oils (VOs), animal fats and waste oil widely accepted as substitute for fossil-derived diesel fuel. It is a renewable and sustainable energy source that is environmentally friendly. Food-fuel strain of conventional VOs has renewed research interest in exploring 350 alternative oil-bearing crops that can be harnessed as diesel fuel substitute, but with less than 100 investigated. Colocynthis citrullus Lanatus, ‘egusi’, has been studied for the first time as a potential biodiesel feedstock. Crude oil from the seeds have been characterized and transesterified using methanol in the presence of sodium methoxide as catalyst. The design of experiment for the optimization of the reaction conditions was conducted using response surface methodology (RSM). A three-level-three-factors face centered central composite design was employed. Catalyst amount (0.25 - 1.8% wt.), reaction temperature (45 – 65 °C) and oil-methanol molar ratio (4 – 10) were studied as important factors influencing the reaction. Fuel properties of egusi melon methyl ester (EMME) were determined in accordance to ASTM D 6751 and EN 14214 standard test methods. The fatty acid profile of EMME was analyzed using gas chromatograph. Also, rheological behaviors of EMME and its blends (B2, B5, B10) in relation to viscosity were studied. The amount of catalyst and reaction temperature was the most significant (P < 0.0001) factors affecting the yield of EMME. Multiple regression analysis was used to develop an empirical mathematical model for predicting methyl ester yield of EMME. The optimum reaction conditions obtained from the model for EMME synthesis were 1:6.54 oil-to-methanol molar ratio, 1.22% catalyst amounts, and 65 ˚C reaction temperature resulting in a yield of 84.01%. Under experimental conditions, methyl esters yield of 84.46 ± 0.075% was obtained on an average with the optimal values. This yield value is well within the range predicted by the model. RSM was found to be a suitable technique for optimizing the transesterification of egusi melon seed oil. The quality and fuel properties of EMME determined were found to satisfy prescribed ASTM (D 6751) and EN 14214 specifications. The viscosity behavior of EMME and its blends with diesel fuel (pseudoplastic and Newtonian in nature) was found to agree with those of other biodiesels reported in literature. From this present study, it was discovered that fuel properties and fatty ester profile of egusi melon biodiesel resemble those of sunflower, soybean and safflower. The kinematic viscosity (KV) of EMME was found to be 3.51 mm2/s (at 40 °C), a value remarkably lower than most biodiesels (above 4.0 mm2/s at 40 °C) reported. In addition, its cloud point is relatively low compared to soybean, rapeseed and sunflower biodiesels. Comparisons of egusi melon biodiesel with Malaysian palm biodiesel were satisfactory with the former offering better cloud point and significantly lower KV than the latter. In this work, the probable potential of Colocynthis citrullus L. seed oil for biodiesel production is clearly presented

Experimental study of thermo-convection performance of hybrid nanofluids of Al2O3-MWCNT/water in a differentially heated square cavity

Please read abstract in the article.The National Research Foundation of South Africa under the Renewable and Sustainable Energy Doctoral Scholarships.http://www.elsevier.com/locate/hmthj2021Mechanical and Aeronautical Engineerin

Inventory of kiln stacks emissions and health risk assessment : case of a cement industry in Southwest Nigeria

Cement production is a significant source of air pollution as both gaseous and particulate materials released are detrimental to the ecosystem. This work was carried out in a cement industry located in Southwest Nigeria. The emission rates of carbon monoxide (CO), nitrogen oxides (NOx), carbon dioxide (CO2) and sulphur oxides (SOx) released from the cement kilns using fuel oil, natural gas (NG) and coal were garnered for a year. Thereafter, the estimated emission quantities of the pollutants were employed to obtain the emission inventory of the cement plant. Uncertainty analysis associated with the emissions was evaluated using Analytica® (4.6). Total amounts of pollutants emitted from the plant were 4.86 tonne (t) (NOx), 18.2 t (SOx), 2.270 Kt (CO2) and 1.17 t (CO). Uncertainty range of –149.38% to 149.38% was connected to all the pollutants. Results showed that the quantities of pollutants discharged from the cement industry were considerably higher than recommended. The evaluated air quality indices for CO, NOx, and SOx implied that the health risk on exposure to these gases was hazardous. This study revealed that NG and wastes are the best fuel for kiln firing to reduce the amounts of pollutants emitted into the microenvironment of the plant.https://www.tandfonline.com/loi/rajs202020-09-05hj2019Mechanical and Aeronautical Engineerin

Optimization of coconut oil ethyl esters reaction variables and prediction model of its blends with diesel fuel for density and kinematic viscosity

<p>This paper presents the synthesis of biodiesel from coconut oil sourced from Nigeria through base-catalyzed transesterification using potassium hydroxide (KOH) as catalyst and ethanol as solvent. Direct transesterification reactions were carried out due to low free fatty acid value (0.65 mg KOH/g oil). The reaction variables optimized were: KOH amount (0.5–2.25 wt.%), reaction temperature (30–80 °C), reaction time (30–70 min) and ethanol to oil molar ratio (3–12). Physico-chemical properties of the coconut oil and fuel properties of the coconut oil ethyl esters (CNOEE) were determined using standard test methods, and the properties of the latter were compared with biodiesel standards. Also, the density and viscosity of diesel fuel blends (B5, B10, B20 and B50) with CNOEE were determined and the viscosities compared with that of the Grunberg and Nissan model. In this study, the optimum reaction variables obtained (KOH amount = 1.0 wt.%, ethanol/oil molar ratio = 6:1, reaction temperature = 70 °C, reaction time = 60 min) gave a biodiesel yield of 97.20% and the fuel properties of CNOEE at the optimum conditions conformed to both ASTM D6751 and EU 14214 standards. There was agreement between the measured and estimated values for the density and viscosities of CNOEE–diesel blends. The results indicate that the density and viscosities of the blends increased with the increased of biodiesel percentage in the blends.</p