OSAROBO IGHODARO

This study investigates the impact of Nigeria’s tropical environment on the performance of marine diesel engines, focusing on how climatic factors such as air temperature, humidity, atmospheric pressure, and seawater temperature influence engine efficiency Nigeria’s coastal regions are characterized by consistently high temperatures, intense humidity, and seasonal rainfall variations all of which can affect combustion efficiency, cooling capacity, and fuel consumption in marine engines. In this study, an analysis was conducted on the thermodynamic effects of ambient air temperature, humidity, pressure, and seawater temperature on marine diesel engine performance. A simulation framework integrating ISO correction principles with OEM performance curves was developed and applied to model daily and seasonal variations in Nigeria’s tropical environment using meteorological data. The simulated results were validated against manufacturer reference conditions, and based on the findings, technical, operational, and maintenance strategies were proposed to enhance marine diesel engine
efficiency under tropical conditions. Overall, the analysis showed that Nigeria’s tropical climate caused a minor but consistent derating of marine diesel engine performance. Air temperatures between 32–34 °C and humidity above 75 % led to about a 2–3 % reduction in power and a 0.1–0.2 % increase in specific fuel oil consumption compared to ISO conditions. High ambient heat and warm seawater (around 30 °C) reduced air density and charge-air cooling efficiency, resulting in slightly higher fuel flow rates. Despite these effects, the Wärtsilä 8L32 demonstrated stable exhaust temperatures and strong load control, indicating good adaptability to tropical conditions.

Nigeria’s energy security is heavily reliant on natural gas, a strategy hampered by supply unpredictability and growing global decarbonisation requirements. To address frequent outages caused by gas supply constraints and CO₂ emissions of 350-400 kg/MWh, a strategic pivot is necessary. This study proposes a transformative approach to addressing these dual challenges by retrofitting the Afam VI Natural Gas Combined Cycle (NGCC) power plant into an innovative Integrated Gasification Combined Cycle (IGCC) system. The study looks into the techno-environmental feasibility of repurposing existing infrastructure to use domestic coal and biomass blends, hence increasing fuel flexibility and lowering the plant’s carbon footprint.
This work applies a rigorous simulation-based technique using EBSILON® Professional. A validated baseline model of the present Afam VI plant, which operates at 49.88% efficiency at base load, was created. This model was later updated to incorporate a gasification unit, air separation unit, syngas clean-up techniques and pre-combustion carbon capture. Necessary modifications were also made to the topping and bottoming cycle of the thermal block for syngas combustion. Thermal analysis was carried out to assess system performance under both design and off-design scenarios. The results shows that the IGCC retrofit model reduces the net plant emission of the natural gas baseline model from about 300kg/MWh to about 50kg/MWh, indicating an 85.7% reduction in CO2 emission with a potential for carbon neutrality using biomass as feedstock. However, this comes off on the back of a trade off with the thermal performance of the plant. The retrofit model was found to have an energy efficiency penalty of about 4% points with respect to the natural gas baseline. This results suggests that retrofit IGCC technology is not only technically feasible, but also strategically important for decarbonising the energy industry. It offers a practical, data-driven strategy for using indigenous energy resources to create a more resilient, sustainable, and secure power system. By presenting a feasible model for deep decarbonisation of existing infrastructure, this effort combines national development aspirations with global climate action, establishing IGCC as a baseline for future flexible and clean power generation.

Heat exchangers are fundamental components in thermal engineering, enabling efficient transfer of heat between fluids across various phase states. Their performance largely depends on the thermal characteristics of the working fluid, and improving these characteristics remains a central research focus. Nanofluids—base fluids enhanced with suspended nanoparticles—have emerged as promising candidates due to their potential to significantly improve heat transfer rates. This study investigates the viability of nanofluids as enhanced working fluids for heat exchanger applications, addressing the persistent challenge of increasing heat transfer efficiency in thermal systems. The methodology involved selecting a shell-and-tube heat exchanger and performing detailed mathematical modelling, numerical simulations, and comparative analyses. Simulations were conducted using ANSYS Fluent, supported by theoretical models such as the Maxwell-Garnett relations, Pak and Cho density formulation, and Brinkman viscosity correlations. Mesh generation, boundary condition setup, and performance evaluation were carried out systematically between July and November 2025. Various nanofluid types and volume fractions were iteratively tested to identify the most thermally efficient fluid configuration for the system.

This research explored the viability of natural fibers for ballistic armor, a traditionally synthetic field. Following a literature review, two natural fibers underwent characterization to assess their mechanical properties. These fibers were then tested to evaluate their ability to stop projectiles,
absorb impact energy, and minimize wearer injury. The results provide insights into the potential of natural fibers for ballistic applications, highlighting areas for improvement like strength and moisture resistance. Future research directions include advanced fiber modification techniques, optimized composite design strategies, and life cycle assessments to promote the development of sustainable and effective natural fiber-based ballistic armor.

Nigeria’s energy security is heavily reliant on natural gas, a strategy hampered by supply unpredictability and growing global decarbonisation requirements. To address frequent outages caused by gas supply constraints and CO₂ emissions of 350-400 kg/MWh, a strategic pivot is necessary. This study proposes a transformative approach to addressing these dual challenges by retrofitting the Afam VI Natural Gas Combined Cycle (NGCC) power plant into an innovative Integrated Gasification Combined Cycle (IGCC) system. The study looks into the techno environmental feasibility of repurposing existing infrastructure to use domestic coal and biomass blends, hence increasing fuel flexibility and lowering the plant’s carbon footprint. This work applies a rigorous simulation-based technique using EBSILON® Professional. A validated baseline model of the present Afam VI plant, which operates at 49.88% efficiency at base load, was created. This model was later updated to incorporate a gasification unit, air separation unit, syngas clean-up techniques and pre-combustion carbon capture. Necessary modifications were also made to the topping and bottoming cycle of the thermal block for syngas combustion. Thermal analysis was carried out to assess system performance under both design and off-design scenarios. The results shows that the IGCC retrofit model reduces the net plant emission of the natural gas baseline model from about 300kg/MWh to about 50kg/MWh, indicating an 85.7% reduction in CO2 emission with a potential for carbon neutrality using biomass as feedstock. However, this comes off on the back of a trade off with the thermal performance of the plant. The retrofit model was found to have an energy efficiency penalty of about 4% points with respect to the natural gas baseline.