https://ir-library.mmust.ac.ke/xmlui/handle/123456789/36 Wed, 06 May 2026 17:28:59 GMT 2026-05-06T17:28:59Z https://ir-library.mmust.ac.ke/xmlui/handle/123456789/3433 OPTIMIZATION OF HYBRID CYCLONE IN REDUCTION OF PARTICULATE FLY ASH IN SUGAR INDUSTRIES IN KENYA OTIENO, JOSEPH ODORO The sugar industry in Kenya faces growing environmental and regulatory pressure due to fly ash emissions from bagasse-fired boilers. Traditional single-stage cyclone separators currently employed in these facilities offer limited particulate collection efficiency—ranging between 50% and 60%—and often fail to capture fine ash particles, resulting in persistent air pollution and adverse health impacts on surrounding communities and industrial workers. This research investigates the design and performance of a hybrid cyclone separator, aiming to enhance particulate capture rates and reduce environmental degradation in Kenya’s sugar belt regions. The study employed a factorial design approach, combining Computational Fluid Dynamics (CFD) simulations and experimental modeling to assess key design parameters, including inlet diameter (150 mm, 200 mm, 250 mm) and cyclone orientation (series vs. parallel). Temperature, pressure, velocity, and density profiles were analyzed across configurations to evaluate their influence on particle separation and gas dynamics. Results revealed a pronounced improvement in efficiency when using the hybrid cyclone in a series configuration, achieving rates between 81.26% and 81.95%—a substantial increase compared to conventional cyclones, which recorded a maximum of 63.69%. Notably, the hybrid design maintained stable gas velocities and operated with slightly lower fluid densities, reinforcing its capability to trap finer particles effectively. Among tested inlet diameters, the 200 mm configuration demonstrated optimal baseline efficiency and fluid dynamic stability. Orientation analysis showed that series connection outperformed parallel setups, with the latter achieving only 30.6% efficiency due to thermal instability and less synchronized vortex formation. The series arrangement enhanced flow regulation, leading to improved pressure gradients and particle capture. A regression-based mathematical model was derived to estimate efficiency using pressure, density, and relative pressure variables, yielding consistent predictive accuracy across all configurations. The model equation: Efficiency (%)} = -3303 + 0.05075P - 1441\rho - 0.05564P_r offers engineers a useful tool for real-time estimation and design optimization. The research concludes that hybrid cyclones configured in series offer a viable and energy-efficient alternative for particulate control in Kenyan sugar mills. Their implementation not only aligns with environmental standards but also enhances occupational safety, reduces equipment corrosion, and supports the industry's move toward sustainable practices. This thesis contributes a scalable and technically grounded solution to air quality challenges in agro-industrial settings, with implications for broader applications in biomass combustion and particulate-laden exhaust management. Tue, 01 Oct 2024 00:00:00 GMT https://ir-library.mmust.ac.ke/xmlui/handle/123456789/3433 2024-10-01T00:00:00Z https://ir-library.mmust.ac.ke/xmlui/handle/123456789/3432 OPTIMIZATION OF BIOGAS PURIFICATION USING WATER-SCRUBBING TECHNOLOGY FOR ENHANCED GAS QUALITY MUTOBERA, CONRAD SAKWA Biogas has been found to be a green source of power. It consists majorly of methane (CH4), carbon dioxide (CO2), hydrogen sulphide (H2S) and water vapour. Use of biogas has never reached its potential with the problem of inherent impurities that compromises its quality and restricts its usage. Purification of biogas is important in ensuring the gas is apt in a number of applications within the renewable energy sector. Amines scrubbing, physical scrubbing, cryogenic separation, pressure swing adsorption, membrane separation and water scrubbing are some of the methods which have been employed to upgrade biogas. Water scrubbing has, however, been highly applied in the enrichment of CH4 due to its nature of availability and ease of use. Various studies have applied water scrubbing to remove impurities from biogas; however, little has been done from these studies to establish the optimal working parameters applicable to small household operators. This study, therefore, focused on optimizing the water scrubbing process for optimal biogas quality using water scrubbing technology. The study optimized the following variables: water flow rate (WFR), the gas flow rate (GFR), pressure (P), and gas retention time (RT). WFR was varied at the rates of 3.5, 4.0, 4.5, 5.0, and 5.5 litres per hour (l/hr), while the GFR was varied at 7.5, 8.0, 8.5, 9.0, and 9.5 litres per minute (l/min). P was varied at 0.04, 0.05, 0.06, 0.07, and 0.08 bar, while RT was varied at 30, 45, 60, 75, and 90 seconds. A set of 30 runs was experimented and the percentage gas composition in the upgraded biogas recorded using a SKY2000-M4-WH multi-gas detector. The results of the experiment were analyzed and optimized using ANOVA, Response Surface Methodology, and Design Expert software version 13. The raw biogas of an initial composition of 80.66% Methane, 15.76% Carbon dioxide, and 10 mg/m3 Hydrogen Sulphide was used as a control experiment. This study found that the optimal CH4 enrichment of 91.45% was observed at the following values of WFR, GFR, P, and RT of 5.0 l/hr, 8.0 l/min, 0.07 bar, and 75 seconds, respectively. A combination of these factors gave the optimal results: CH4 improved by 10.79% (from 80.66% to 91.45%), CO2 had the lowest value of 6.91%, and H2S was zero mg/m3. The predictive models developed revealed that methane enrichment increases with the WFR and RT, while it decreases with an increase in the GFR. It is recommended that further research be conducted to establish the rank of influence of the factors for further optimization. Sat, 01 Nov 2025 00:00:00 GMT https://ir-library.mmust.ac.ke/xmlui/handle/123456789/3432 2025-11-01T00:00:00Z https://ir-library.mmust.ac.ke/xmlui/handle/123456789/3431 OPTIMAL SIZING AND ANALYSIS OF A SUSTAINABLE SOLAR PHOTO VOLTAIC-BIOMASS HYBRID ENERGY SYSTEM FOR LEARNING INSTITUTIONS Omondi, Michael Juma Access to quality energy is a necessity for the growing world. There is an increasing demand for clean and quality energy due to the ever-growing world population and development of new technologies. However, energy access is still a significant challenge globally and to learning institutions. Learning Institutions suffer from limited to no access to electricity due to unreliability of the grid extension that supply them with power. The main back up system for learning Institutions in Kenya is often diesel generators, which have high maintenance, and running costs in addition to emitting harmful gaseous emissions to the environment. To achieve environmental safety, sustainability and quality energy, renewable energy resources technologies need to be developed to help in the reduction of carbon footprints. The main objective of this research is to design and optimize a renewable energy system that can be used to power learning institutions which is also less sensitive to external conditions such as changes in solar irradiation levels and changing inflation costs. This research presents a sustainable, less sensitive, and optimal configuration of a hybrid renewable energy system (Solar PV-Biomass energy system) with storage needed to power Masinde Muliro University of science and Technology. It moreover, presents a techno economic analysis for achieving the least cost configuration which is sustainable on using historical demand and supply data for the University. The results show that due to the high solar irradiance within the region (5.9 kWh/m2 /day) and high levels of biomass due to high university population, a larger percent of energy shall be generated by the two energy resources. This energy mix was compared with other nine energy mix based on economical, technical and sustainability parameters. The results show that the integration of 360 kW of solar PV array, 540 kW of Biomass Generator, 142 kW converter and 576 strings of 1 kW lead-acid batteries storage bank is the best configuration that leads to an optimum configuration with the LCOE of 0.1026 $/kWh in MMUST. Key words: solar, biomass, analysis, optimization, sensitivity, sustainability Fri, 01 Aug 2025 00:00:00 GMT https://ir-library.mmust.ac.ke/xmlui/handle/123456789/3431 2025-08-01T00:00:00Z https://ir-library.mmust.ac.ke/xmlui/handle/123456789/3427 DETERMINATION OF COMBUSTION PROPERTIES OF BLENDED BRIQUETTES OF SAWDUST, MAIZE STALKS, AND COFFEE HUSKS CHERUIYOT, RONOH BENARD The tea industry in Kericho is among the main consumers of firewood for its intensive thermal energy demand used in industrial steam boilers. Concerns over firewood depletion have led tea producers to switch to alternate fuels for boilers. Briquettes made from biomass leftovers are among the possible options; however, they are not yet widely adopted and implemented. This study found a potential source of briquettes for fire boilers that will use agricultural byproducts produced in Kericho. The combustion properties of blended briquettes made from sawdust, maize stalks, and coffee husks were used to determine the optimal ratio. Among the primary reasons is the depletion of firewood, with a rise in the number of tea industry projects in Kericho County, resulting in an 8% reduction in forest cover. Blended briquettes have gained attention as a sustainable alternative to traditional fuels due to their potential for reducing environmental impact by utilizing agricultural and forestry residues and reducing the dependency on wood pellets. The physical properties investigated in this research included gross calorific value, moisture content, fixed carbon, and volatile matter of the blended briquettes. Experiment design and analysis were done using Design-Expert® Software Version 10-Stat-Ease.The response surface methodology was utilized to investigate how burning affects the physical properties of mixed briquettes manufactured from coffee husks, maize stalks, and sawdust. The interaction of the parameters was also explored. Blended briquettes were developed from coffee husks, maize stalks, and sawdust, measuring 45mm by 45mm by 35mm.From the analysis of individual briquettes, Individual briquettes' moisture content ranges from 10.01 % and 12.59%. Coffee husks gave 10.01%, Maize stalks briquettes 12.59% and coffee husks 10.01. The volatile matter is between 71.25% and 78.30% where sawdust gave 77.05%, coffee husks 78.30% and maize stalks 71.25%. The fixed carbons range between 8.58% and 13.08%. Sawdust gave 9.36%, coffee husks 8.58% and maize stalks at 13.08%. The Calorific Value is between 3.8652 kCal/g and 4.2149 kCal/g. Sawdust generated 4.1589 kCal/g, Coffee Husks 4.2129 kCal/g and maize stalks 3.8652 kCal/g. The optimal mix ratio of sawdust: coffee husks: maize stalks is 350:169.142:150. This ratio gives a moisture content of 9.65%, a gross calorific value of 4.356 kCal/g, a fixed Carbon of 6.986%, and a volatile matter of 79.115%. This has verified that blended briquette fuel has better combustion properties than individual samples. The knowledge gained from this research has contributed to the development of renewable energy technologies and supports the transition towards a more environmentally friendly and resource-efficient society. Sat, 01 Nov 2025 00:00:00 GMT https://ir-library.mmust.ac.ke/xmlui/handle/123456789/3427 2025-11-01T00:00:00Z