Browsing by Author "Okure, Mackay A.E."

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    Comparison Of Kiln-Derived And Gasifier-Derived Biochars As Soil Amendments In The Humid Tropics
    (Biomass and Bioenergy, 2012) Deal, Christopher; Brewer, Catherine E.; Brown, Robert C.; Okure, Mackay A.E.; Amoding, Alice
    Biochar is the carbonaceous solid byproduct from thermal treatment of biomass that is produced specifically for application to soils. Studies have shown that when biochar is added to soils, it is able to increase yields, improve soil properties, and effectively store carbon for hundreds to thousands of years. This study compared the performance of biochar from five different feedstocks (coffee husks, maize cobs, eucalyptus wood, groundnut shells, and rice husks) produced in a traditional kiln and biochar from two different feedstocks (maize cobs and eucalyptus wood) produced in a downdraft gasifier. This research, conducted at Makerere University in Kampala, Uganda, was aimed at investigating the potential of biochar as a soil amendment in the humid tropics. Biochar samples were combined with undisturbed soil in a 45-day pot experiment to compare effects on maize growth. On average, soils amended with gasifier-produced biochar had higher yields than the unamended soil and soils amended with kiln-produced biochar. Comparing kiln-produced chars from different feedstocks, the coffee husk chars were the most productive. Results indicated that the soluble ash content of the biochar had the greatest influence on soil productivity. Ugandan soils, like most soils in the humid tropics, are strongly acidic (pH = 4.7), and the increase in pH caused by the soluble ash in the biochar provided for more favorable growing conditions and higher nutrient availability.
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    Role of Intangible Assets in the Adoption of Advanced Manufacturing Technologies (AMT’s) in Developing Countries: Case Study of Uganda.
    (Second International Conference on Advances in Engineering and Technology, 2011) Mukasa, Norbert; Okure, Mackay A.E.; Elvenes, Bjørn Otto
    This study analyses the machine tool driven industry in a developing country. It models the relationships between measures of Advanced Manufacturing Technology (AMT) penetration, adoption trends and three sets of predictor variables that are intangible. The study was carried out in 39 firms found to be using machine tools. The results show that education levels of blue collar workers, engineers and managers were instrumental to the investment in systems, devices and stations (SDS), while clerical employees are instrumental in integrating these technologies. The Chief Executive Officer (CEO) and environmental issues were strong influences. The strongest single strategic motivation that drove Ugandan firms to invest in AMT’s was the superior image of the firm followed by reduction in labour costs. Finally the study provides interesting insights into the relatively atypical parameters that characterize this industry in a developing country. .
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    Small-scale CHP for Rural Electrification in Uganda – The State-ofthe- art and Prospective Development
    (In Second International Conference on Advances in Engineering and Technology, Working Paper., 2011) Musinguzi, Wilson B.; Okure, Mackay A.E.; Sebbit, Adam; Løvås, Terese
    Worldover, small-scale CHP systems are undergoing rapid development, and are emerging on the market with promising prospects for the near future. The choice of a suitable CHP system is driven by the need and local conditions at the target end user, keeping in mind that the system integration should have a good balance of being most efficient, reliable, cost effective, socially beneficial, least polluting and sustainable in the long run. In developing countries, small-scale biomass-fuelled CHP systems have a particular strong relevance in improving the quality of life, especially among rural communities. This paper presents the recent advances in small scale CHP process integration for decentralized power generation. It also presents an exergy analysis of a prospective CHP system that has the potential of providing relatively higher efficiency and minimal operational difficulties and thus attractive for rural electrification in Uganda. The target generation capacity is 100 kWe sufficient to meet electricity needs of a rural community of 250 households. Stepwise procedure with simulation using Aspen Plus is used in the analysis of this CHP cycle. The results show that the proposed process integration has the promise of efficiently utilizing the exergy generated.
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    Thermal characterization of Uganda's Acacia hockii, Combretum molle, Eucalyptus grandis and Terminalia glaucescens for gasification
    (Biomass and Bioenergy, 2012) Musinguzi, Wilson B.; Okure, Mackay A.E.; Wang, Liang; Sebbit, Adam; Løvås, Terese
    In this paper, thermal characterization of four Ugandan woody biomass species was carried out in order to ascertain their suitability for gasification for small-scale biopower generation. The analyses and tests covered the aspects of proximate analysis, ultimate analysis, heating value, Thermogravimetric Analyses (TGA), ash melting and chemical composition. Eucalyptus grandis revealed ideal properties that make it the most promising wood specie for gasification applications. Furthermore, the low ash content in E. grandis significantly minimizes the possibilities of ash deposits on the gasifier and heat exchanger surfaces. The high fixed carbon in Terminalia glaucescens, Acacia hockii and Combretum molle makes these species ideal for charcoal making (pyrolysis). Due to high ash melting temperatures demonstrated by these samples, their pyrolysis and gasification can therefore take place with minimal worry of the ash related problems.
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    Thermodynamic Modeling of Allothermal Steam Gasification in a Downdraft Fixed-bed Gasifier
    (Trans Tech Publications Ltd., 2014) Musinguzi, Wilson B.; Okure, Mackay A.E.; Sebbit, Adam; Løvås, Terese; Silva, Izael Da
    A process of converting a solid carbonaceous fuel into a gaseous energy carrier in presence of a gasifying medium at high temperature is called gasification. The resulting gaseous energy carrier, known as producer gas, is more versatile in its use than the original solid fuel. Gasification is widely considered as a more efficient and less polluting initial thermochemical upstream process of converting biomass to electricity. The objective of this study was to investigate the process of allothermal steam gasification in a fixed-bed downdraft gasifier for improved quality (HHV, high hydrogen content) of the producer gas generated. The study involved thermodynamic equilibrium modeling based on equilibrium approach in which the concentrations of the gaseous components in the producer gas at equilibrium temperature are determined based on balancing the moles in the overall gasification equation. The results obtained suggest that the maximum equilibrium yield of producer gas with high energy density is attained at a gasification temperature of around 820oC and a steam/biomass ratio of 0.825 mol/mol. The equilibrium yield was richer in hydrogen at 52.23%vol, and with a higher heating value of 11.6 MJ/Nm3. Preliminary validation of the model results using experimental data from literature shows a close relationship. The study has further shown the advantage of using steam as a gasifying medium towards the improved quality of the producer gas generated.