Department of Mining, Chemical and Petroleum Engineering

Permanent URI for this communityhttps://hdl.handle.net/20.500.12504/144

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    Assessment of healthcare waste Pyrotec model 8 incinerator efficiency as a performance indicator at Muhimbili National Referral Hospital in Dar es Salaam, Tanzania
    (African Journal of Environmental Science and Technology, 2021-09-27) Wanasolo, William; Manyele, Samwel Victor
    The performance of a healthcare waste Pyrotec Model 8 incinerator at Muhimbili national referral hospital in Dar es Salaam, Tanzania, was investigated using two different types of healthcare wastes namely sharps waste and other waste (mass/weight) and as fractions. The other independent factor used in the investigation was diesel oil consumption. The incinerator performance was evaluated by determining how these factors affected the amount of ash residue, the percentage of weight reduction, incinerator capacity and efficiency. The numerical quantities used for independent variables were randomly selected which included low, mid and high levels. The Factorial method with Mixture Historical Data Design type of research methodology was selected for data analysis. The analysis tools included Design Expert Version 7.1 and SigmaPlot 10.0. Results showed that weight reduction increased with increase in sharps waste for all quantities of the fraction of sharps waste investigated. It was concluded that the level of other waste charged had no significant effect (p > 0.05) on the percentage of weight reduction at quantities of total waste below 940 kg/weight but in the presence of high levels of total waste above 960 kg/weight there was a possible interactive effect that influenced the observed high percentage of weight reduction. As a recommendation, it is better to operate the Pyrotec Model 8 incinerator in terms of weight of sharps waste than in terms of the fraction of sharps waste.
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    Optimization of Pyrolysis and Selected Physicochemical Properties of Groundnut Shells, Coffee and Rice Husks for Biochar Production
    (Jordan Journal of Mechanical and Industrial Engineering, 2023-09) John, Chrysostom Opedun; William, Wanasolo; Aldo, Okullo Apita; Timothy, Omara
    Biochar is a solid biofuel that can be obtained from pyrolysis of lignocellulosic feedstocks. In this study, pyrolysis of agricultural wastes (groundnut shells, coffee and rice husks) and their physiochemical characterization was done. Parameters that influenced biochar yields were optimized using response surface methodology and Box-Behnken design. The results obtained showed that rice husks had the highest ash and total solids content of 22.94% and 89.54%, respectively. Coffee husks had the lowest ash and total solids (1.58% and 87.69%) but the highest cellulose content (40.45%). Groundnut shells and rice husks had mean cellulose contents of 28.28% and 20.81%. Moisture content was stable across all the biomass samples with 10.46%, 12.31% and 12.49% recorded for rice and coffee husks, and groundnut shells. Basing on the overall interactive effect of particle size, moisture and cellulose contents, the most optimal interaction that yielded the highest quantity of biochar was found to be at 0.36 mm, 10.18% and 31.51% for particle size, moisture and cellulose contents, respectively. In these interactions, cellulose levels corresponded with groundnut shells as the best biomass material for producing biochar. The study recommends the use of ground nut shells for pyrolysis to produce high yields of biochar for industrial and agricultural applications.
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    Mechanistic modeling of crack propagation in hydraulically fractured reservoirs for predicting inter-well fracture communication during infill well stimulation
    (Geomechanics for Energy and the Environment, 2026-04-20) Pidho, Justin Jordan; Wanasolo, William; Yan, Chuanliang; Cheng, Yuanfang
    Inter well fracture communication is a persistent challenge in multi well infill stimulation, often reducing production efficiency and compromising reservoir integrity. This study develops a mechanistic framework based on the Extended Finite Element Method (XFEM) with phantom node enrichment to simulate multi fracture propagation between neighboring horizontal wells. The model couples poroelastic rock deformation, fracture-matrix fluid exchange, pressure dependent leak off, and fracture propagation governed by a traction-separation law, providing a fully integrated representation of hydraulic fracturing processes. Parametric analyses reveal that zero-stagger distance with simultaneous injection promotes complete fracture linking, while larger offsets or scheduled treatments mitigate communication through stress shadow effects. Increasing rock tensile strength enhances fracture repulsion and reduces tip to tip linking. Distinct pressure signatures differentiate linking fractures, which exhibit localized sagging, from non linking fractures with monotonic gradients. The framework was validated against Displacement Discontinuity Method (DDM) benchmarks, Kristianovich-Geertsma-de Klerk (KGD) analytical solutions, and field measured pressure data from the Daqing Oilfield, demonstrating strong goodness of fit and confirming model fidelity. This work finds useful application in designing perforation patterns, optimizing cluster spacing, and scheduling treatments in unconventional shale reservoirs. By enabling accurate prediction of fracture linking, coalescence, and repulsion, the framework provides practical guidance for maximizing stimulated reservoir volume while controlling unintended inter well interference.