| dc.description.abstract | 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. | en_US |
