Browsing by Author "Bekele Ayele (PhD) Co-Advisor"

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    Determination of Coal Rank and Operational Efficiency through Blending Techniques in the ET-Coal Washing Plant in Dawuro, Ethiopia
    (Addis Ababa University, 2025-03) Berhanu Abate; Bisrat Kebede (PhD; Bekele Ayele (PhD) Co-Advisor
    The study investigates the impact of blending and subsequent washing and flotation processes on coal quality. Four raw coal samples sourced from different seams were blended to create a uni-form feed before undergoing flotation. The study provides laboratory results of coal samples be-fore and after blending, washed by ET- Washing plant, and flotation treatments, highlighting significant improvements in key quality parameters, such as calorific value, ash content, sulfur levels, moisture content, and volatile matter. The flotation process, in particular, demonstrated considerable advantages in reducing ash and moisture content while increasing calorific value, making the coal more suitable for energy production. However, challenges related to sulfur con-tent and volatile matter remain. Additionally, environmental concerns such as water contamina-tion, air pollution, and solid waste management were addressed, with recommendations for the implementation of flotation circuits, desulfurization, and efficient waste management practices to minimize environmental impact. Economic analysis of the plant’s operation, including capital and operating costs, demonstrated that while the current process is cost-effective, the addition of flotation could enhance coal recovery and overall revenue. The study concludes that flotation provides the most significant improvements in coal quality and efficiency, making it a viable op-tion for enhancing the plant’s overall operational and economic performance.
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    Enhancing The Caloric Value of Coal Deposit Using Flotation Method in Lalo District, South-Western Ethiopia
    (Addis Ababa University, 2025-02) Megersa Biratu; Melese Alemayehu (PhD); Bekele Ayele (PhD) Co-Advisor
    Lalo coal reserves are mainly lignite and contain high ash coals therefore, it is important to enhance these low-quality coals. Coal applications are impacted by high ash content; hence improvements are required to lower the ash content of coal in our nation. Tests were carried out to investigate and determine the effect of parameters like particle size and collector dosage on reducing ash content from coal. The particle size observed to have the most significant role in coal ash, followed by the collector dosage. The optimum particle size and collector dosage values were -100+75μm and 7ml respectively. The results from the flotation study on a laboratory scale at optimized conditions revealed an increase in carbon content from 26.16% to 39.07%, decrease ash content and sulfur content from 25.75% to 20.09% and 0.47% to 0.21% respectively. Using a high ash content coal sample from the Lalo district coalfield, flotation is used in this study to improve the quality of coal samples to remove the ash and impurities.