Browsing by Author "Towoju, O. A."

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Bridging Nigeria energy gap by utilizing her coal
(2017) Towoju, O. A.; Petinrin, M. O.
Many nations who meet their energy generation requirements are one way or the other tapping from the vast resources which is inherent in coal. A wide gap exists between the energy requirement of the Nigerian populace and the generated amount. This can be bridged by the utilization of its vast amount of bituminous coal in her reserves, with favourable properties of low percentage moisture and ash which is an advantage in terms of handling costs, ease of transportation and better overall system efficiency. The percentage moisture value for the analyzed sample was 5.0 percent while the percentage ash value was 6.6 percent. Both determined values are relatively low when compared to results of the analysis reported for some other countries coal.
Climate change mitigation with carbon capture: an overview
(2023) Towoju, O. A.; Petinrin, M. O.
The world is at the verge of catastrophe occasioned by the effect of climate change. Drastic action needs to be taken to reverse this ugly trend. Some of the proffered solutions to global warming is the adoption of renewable energy usage and a stop of fossil fuels combustion. However, the low capacity factor and energy return has been the bane on the usage of some renewable energy sources. A leeway however, exists in the technology of removal of greenhouse gases referred to as Carbon Capture. The widely adopted method being at point source because of its high concentration favouring easier processes of removal. This technology has received increased attention over the years as evident from data for the past five years. However, this technology alone cannot guarantee atmospheric CO2 levels required to maintain global temperature rise below the 1.50C mark. Negative emission technology processes of which the Direct Air Capture (DAC) is one needs to be developed. The infancy of the DAC technology and the uncertainties that surrounds its cost still pose as challenges. The cost of removing a tonne of CO2 with DAC technology can be as high as $600, this is unsustainable and has to be drastically reduced. While it is projected that DAC technology can take out 980 Metric Tonne (MT) CO2/annum by 2050, current figures stand at 0.008 MT. It is our view that the development of solid adsorbents and the harnessing of the thermal energy inherent in the sun can be a game changer.
Control modelling of coupled shell and tube heat exchangers using combined neural network and fuzzy logic
(2022) Petinrin, M. O.; Oke, O. S.; Adebayo, A. S.; Towoju, O. A.; Ismail, O. S.
Control of the temperature of the outlet fluid in heat exchanger network is very important to maintain safety of equipment and meet the optimal process requirement. Conventional PID controllers have the limitations of meeting up with wide range of precision temperature control requirements, and then the predictive controllers have recently emerged as promising alternatives for advanced process control in heat exchanger systems and other industrial applications. This paper focuses on the control of output temperature of coupled shell and tube heat exchanger by combining fuzzy logic and Neural Network control system. To achieve effective control, transfer functions from the energy balance equations of the heat exchanger unit and other components were obtained. Simulation of the control process was carried out using Simulink interface of MATLAB. The time response analysis in comparison with variants of conventional PID controllers shows that combination of Neural Network and fuzzy logic controllers can efficiently improve the performance of the shell and tube heat exchanger system while in with 0.505% overshoot and less settling time of 12.74 s, and in parallel with the same overshoot of 0.505% and settling time of 11.37 s. The demonstration of the lower error indices of the neuro-fuzzy controlled system also indicated its better performance.
Numerical study of the effect of changing tube pitches on heat and flow characteristics from tube bundles in cross flow
(2019) Petinrin, M. O.; Towoju, O. A.; Ajiboye, S. A.; Zebulun, O. E.
Tube bundles are found in various heat transfer equipment for thermal energy transfer between fluids. However, the inter-spatial arrangement of the tubes of any tube bundle is a determining factor for its thermal and hydraulic performance. In this paper, the effect of varying the transverse and longitudinal pitches downstream staggered circular tube bundle on the heat transfer and flow characteristic was numerically analyzed. Seven variations of tube arrangements were studied by changing the tube pitches within a Reynolds number range of 7 381 to 22 214. The analyses were carried out using the k-ε equation model imposed with the realizability constraint and were solved with finite volume CFD code, COMSOL Multiphysics. The results obtained were found to be in good agreement with existing correlations. The tube bundles with decreasing pitches demonstrated better heat transfer performance while those with increasing pitches exhibited a lower friction factor. Thus, the best thermal-hydraulic performance was obtained from increasing pitch arrangements.
Thermal lesion of renal tumour as a function of catheter material property
(2018-09) Towoju, O. A.; Petinrin, M. O.
The extent of lesion achieved during microwave ablation is dependent on some factors which include the time period of application, its intensity, antenna geometry, and relative permittivity of the tissue. Several studies have been conducted on microwave ablation for the treatment of tumours and have focused on different antenna geometries, its intensity, and time of application. This work seeks to find a correlation between the relative permittivity of the catheter and the temperature distribution which determines necrosis of the tissue by using Tefzel ETFE, Teflon FEP, PFA Teflon type A, PFA Teflon type B, Teflon AF, and PTFE Teflon type B while modelling using COMSOL Multiphysics. The extent of the thermal lesion was observed to be dependent on the relative permittivity of the catheter material, with Tefzel ETFE giving the best performance and Teflon AF providing the least.