Ibrahim Kolawole Muritala

Valorisation of local and low-cost eco-materials have become an imperative for the sustainable development of Concentrating Solar Power (CSP) in West Africa. In this study, the compatibility tests were carried out. These involve the application of jatropha curcas oil (JCCO) and ceramic balls, which were developed from clay coal bottom ash and sands with a focus on Burkina dune sand ceramic. The aim was to assess the applicability of using JCCO as heat transfer fluid in CSPs with direct thermocline thermal energy storage. The tests involve the use of a small container to put in contact with Jatropha oil with ceramic balls for 2160 hours and at 210 °C. From the chemical properties’ analysis, the peroxide value in the oil decreases with aging time while the acidity increase. However, the acidity remains below the limited value that is 25 mg KOH.g^-1. Therefore, thermal properties that drive heat transfer and rheological properties (density, thermal conductivity, kinematic viscosity and so on) were not adjusted significantly at the storage temperature (of about 210°C). Thermal stability temperature decreased to 261.93°C for the oil aged alone as against 263.41 °C for the one that was put in contact with filler material. In the nutshell, there is no incompatibility between JCCO, and the new thermal energy storage material (TESM) developed. These couple of materials could be suitable for thermocline energy storage in CSP plant and for other applications like there use in solar cooker box.

Aim: The use of synthetic catalysts in pyrolysis of waste plastics into hydrocarbon fuels is the common practice, these synthetic/ commercial catalysts are not readily available in Nigeria. The aim of this research paper is to prepare and characterize and test the catalytic performance of a locally made catalyst for waste plastic to hydrocarbon fuel pyrolysis. Study Design: locally made catalyst was prepared from coconut shells, its elemental composition, structural morphology and pore properties investigated using appropriate instruments and methods. Place and Duration: The experiments were carried out at the Petroleum Development Laboratory, situated at the Gas Engineering building, University of Port-Harcourt Nigeria. It took about 18 months to complete this study. Methodology: Thermal and chemical activation methods were used to prepare the local catalyst from coconut shells. Scanning electron microscopy method was used to investigate the morphology and texture of the coconut shell activated carbon catalyst. Response Surface Method (RSM) in design expert software 12.0 was used to design the experiment, and investigate the effect of operating parameters on the response variable. Results: The assessment of coconut shell activated carbon shows it can be used as an alternate to synthetic catalysts. This is because more than 60 % fuel oil was recovered when it was used in the pyrolysis of waste sac bags Conclusion: Coconut shell activated carbon is effective in the conversion of waste sac bags high purity hydrocarbon fuels such as aviation kerosene.

Emerging technology in the electronic industry has led to miniaturization of electronic devices such as iPhones and laptops. Heat dissipation is required to maintain high performance and long-term reliability of these devices. Micro heat sinks and novel working fluids such as nanofluids are becoming popular. Until recent times the full potential of hybrid nanofluid in heat transfer has not yet been exploited. In order to address the lack of adequate modeling data in this field, the aim of this study is to systematically model and investigate computational heat transfer characteristics of Al₂O₃-Cu/water hybrid nanofluid in micro heat sink. Volume concentration in the range of 0.1%-0.5% was used for the working fluid. Hexagonal micro-pin fin heat sink with staggered arrangement was simulated in ANSYS Fluent. Reliable experimental result from literature was used to validate the accuracy of the results. The most obvious finding to emerge from this study is that the Nusselt number increases with increase in Reynolds number and this observation is consistently the same at different concentrations and pin spacing. Lower transverse pitch was observed to dominate the enhancement of Nusselt number. There was a 10% increase in heat transfer coefficient at 0.5% nanofluid concentration when compared to 0.1%. This phenomenon is highly influenced by the transition of the Re into turbulent situation which eventually enhances the heat transfer characteristics. Also, lower transverse pitch promotes swirling flow situation. At 0.5% hybrid nanofluid concentration, it was observed that the Nusselt number increased from 14.00 at transverse pitch of 3.81 mm to 17.00 at a transverse pitch of 1.81 mm and this corresponds to 16.05% enhancement of Nusselt number. The pressure drop penalty of the working fluid is a result of increase in viscous effect of the hybrid nanofluid, especially at high concentration.