Faculty of Engineering and Built Environment
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Item Development of integrated model and framework for sustainable energy resources and systems planning(2024-05) Akpan, Joseph Samuel; Oludolapo, Olanrewaju AkanniSustainable energy development (SED) is a crucial component of the Sustainable Development Goals (SDG), aiming to maintain economic and social progress while protecting the environment and mitigating climate change's effects. SED serves as a transition paradigm for sustainable development, providing a blueprint for energy peace and prosperity for people and all uses. The first objective of this dissertation is to identify 10 interlinked themes of SED and explore 2 of them, which are the least studied in existing SED reviews. These two themes include energy financing and commitment to climate change and the need for 100% renewable energy (RE), a part of the decarbonization strategy towards the 1.5 - 2.0 °C Scenario. The study suggests that the current G20 countries' contributions, if done continuously per annum, in addition to 80% more funding from private investment of the same amount in the 1.5°C scenario financial requirement for clean energy, is sufficient to limit global warming. In addition to the present drive for 100% RE for all purposes, an emphasis is placed on addressing other issues, such as energy storage options, developing countries' development agenda, and regional security stability to prevent energy wars. Emerging SED decarbonization strategies are presented across power, transport, building, and industrial sectors. This part concludes with a summary of SED progress and directions for future research, mainly the need for re-defining Nationally Determined Contribution (NDC) through a centralized global or regional stock-taking strategy for greenhouse gas emissions reduction. Consequently, the next study attempts to address the limitations of the current NDC by formulating a policy hypothesis and applying it to an integrated assessment tool (here, termed the environmental model) for strategic stock-taking in reducing GHG emissions. In developing this indexing model, being the first objective of this thesis, we analysed the potential impact of Nationally Determined Contributions (NDCs) under the Paris Agreement on global temperature rise used as the key model input parameters with countries' historical data and other parameters such as GDP, population growth. With the use of an integrated assessment tool based on the concept of system dynamics, the analysis constructs a framework to project global temperature changes under five policy scenarios, namely baseline, current (announced energy policies 1 and 2), and optimum (2.0 0 C Scenario), and most optimum (1.5 0 C) case scenarios. The hypothesis is formulated based on the analysis of current, announced, and best-case global and or applicable national policy scenarios. The model aims to address critical questions regarding the effectiveness of the on-going NDCs commitments in limiting global temperature rise to well below 2 0 C, in alignment with the Paris Agreement's goals. The simulation results offer a roadmap for optimizing the current NDCs in global and national energy policies and treaties, fostering international collaboration, and reinforcing the global commitment to combating climate change. Leveraging on the preceding simulation result of the environmental model, a novel emissions budgeting (EB) model tool (here, termed the economic model) was introduced as a simplified approach for the determination of the economic attractiveness of the policy scenarios of the environmental model. Hence, the second objective, which was to determine the economic benefit of policy scenarios, was achieved. Some advanced countries’ rapid population, economic growth, and energy consumption from mostly 100% electricity that is majorly fossil-based contributes significantly to global CO 2 emissions. In contrast, the case in most developing countries is different. For instance, electricity access in Africa is less than 60%. Hence, this presents challenges and opportunities for achieving the United Nations’ Sustainable Development Goals (SDGs) 7 and 13 of generating all energy from cleaner or low-carbon sources to reduce CO 2 emissions in all countries and combating climate change consequences. Therefore, considering the peculiar situation of other developmental goals, such as increasing population access to electricity while being obliged with the need to transit to complete renewable energy, as our third objective, we explored the idea and transition paradigm of reaching a 100% renewable energy that is void of unjust energy transitioning, climate injustice, and unbiased drive for increasing renewables energy penetration in the global energy mix. The increasing need for renewable energies has been widely acknowledged to greatly advance the climate change agenda as increasing clean energy usage depletes the accumulation of GHG in the atmosphere. Alongside reducing the accumulation of GHG, increasing RE share in the national mix has constantly become the core of many countries' energy policies and the agenda of many of the NDCs reported by countries. Presently, about 30 countries already with over 70% of their national electricity mix from RE. A part of this has birthed a new paradigm and an emerging field of 100% RE for all purposes, recently receiving much attention from academia and in public discourse. Upon establishing the need for analysing the transition towards 100% RE, the thesis demonstrated this conceptual idea through a model (here, termed the energy model) to analyse the possibilities for a 100% renewable energy system at the global level. Because several studies have already done such analysis, however, this has hardly been directly linked to the climate scenarios. Therefore, this thesis bridged this gap in the literature by synthesising the energy transition at different percentage shares in the global primary energy mix over time with the effect on global temperature levels. The rationale behind this was to present a discussion on the pathway possibilities and challenges of achieving 100% RE and whether it is possible to meet the total global energy demand through RE, with what effect on the climate scenarios. To do this analysis, we further define our hypothesis using baseline, optimum, more optimum, and extreme optimum path scenarios to ascertain such possibilities. Finally, we used an integrated assessment model based on the principles of system dynamics to analyse these hypotheses and to find the implications of each action or scenario on other factors such as global temperature, GHG emissions, energy storage breakthrough while keeping the population growth at maximum possible value of 12.4 billion persons by 2100 with GDP growth rate not less than 1.5%. The findings are valuable in helping us discuss if 100% RE can be a reality and what the implications are. Our results show that in the baseline current scenarios, the global average temperature will most likely be kept at 3.3 0 C. Hence, the world would need very urgent and unprecedented efforts beyond the current baseline of business as usual. Interestingly, our findings also indicate that to stay within the 1.5 and 2.0 0 C Scenarios, the world may need just between (58.6 - 77.3) % and (62.7 - 82.8) %, respectively, in the global energy mix. For the most optimistic scenario, (75.5 - 99.8) % RE may be required, and this is able to keep the temperature rise even well below 1.5 0 C but at 1.1 0 C. The 1.1 0 C possibility is quite highly ambitious, in my opinion, because it requires the intensity of global mix energy generation of about 6627 extra joules from renewables only. The major challenge with the idea of 100% RE for all purposes is that achieving such a feat requires a more diverse approach and scarcely are there 100% RE studies that incorporate holistically the interrelation of several pertinent strategies. Therefore, there exists a need to meet both the technical and non-technical requirements. In order to address this shortcoming, our third objective introduces six methodological or evaluation mechanisms (herein, identified as 100% RE evaluation metrics) suitable for existing and future 100% renewable energy analysis. It then reviews energy modelling tools to identify their applicability to 100% RE analysis. The perspectives presented in this thesis are valuable in developing a common integrated methodology and modelling tool for analysing full renewable energy adoption in countries or regions with best trade-offs, using performance indices that have not been previously used. The proposed metrics could also help with proper national and regional energy resources and system planning for new energy projects and installations, contributing to sustainable development. The framework and narrative, presented in the form of a model within this dissertation, make a noteworthy contribution to the ongoing discourse surrounding the energy transition as, to the best of my knowledge, this concept has not been presented this way. The results from this dissertation can be further investigated through a streamlined application of the approach at individual country or regional level to facilitate inclusive and climate-responsive planning and execution strategies for sustainable energy and electricity generation, distribution, and utilization at both national and urban levels. The implications of the findings have the potential to inform the United Nations Framework on Climate Change Convention (UNFCCC) and Conference of Parties (COP) policies in better ways of promoting equitable support for countries, regions, energy consumers, utilities, and prosumers.Item Feasibility of blue energy production using reverse electrodialysis In KwaZulu-Natal coastal region : modelling study using Comsol multiphysics(2024-05) Ngcobo, Lungisani; Ngema, Peterson Thokozani; Tumba, KanikiRenewable energies have gained an increasing focus in recent years, due to the climate crisis contributed or associated with the current energy generation sources in South Africa. Thus, in this thesis, a renewable energy source called salinity gradient energy or blue energy will be presented and studied. The main objectives outlined in this dissertation were to evaluate the theoretical potential of electric energy production from the KwaZulu Natal rivers which are uThukela, uMvoti, uMkhomazi, Amanzimtoti, Umgeni, and uMfolozi. Finally, to optimize and simulate RED membrane and design reverse electrodialysis membranes and feeding pumps. In terms of the theoretical potential for producing electricity in the studied estuaries, it was concluded that the uThukela estuary has a considerably higher potential than the others. So, by this information, the possibility of designing the pilot plant in this estuary was studied, noting that the location of the pilot plant where the energy produced is greater and the capital cost are lower is at the mouth of the uThukela river. As for the pilot plant of RED, it was concluded that it is economically viable since the profit/loss found was R0 which is a break-even point, the plant is not generating a profit, but it’s also not generating a loss and since the focus for now is to try generating power. It’s economically viable in the sense that it covers its costs, but it is not profitable in terms of generating surplus revenue. It was concluded that using cheap and very thin membranes with high fluxes can increase the performance of the reverse electrodialysis. Also, the performance can be increased by using more than two reverse electrodialysis stacks instead of one.Item Development of an Intelligent Standalone Solar Photovoltaic 48V DC microgrid system(2024-05) Makhanya, Thandeka; Pillay, N; Sewsunker, RWith load shedding negatively affecting South Africans there are many concerns regarding stable power delivery to residential households. Amid all the power delivery concerns some rural communities are still not connected to the existing power infrastructure. Implementation of newer efficient clean energy sources is in demand. A standalone Photovoltaic (PV) Solar distributed renewable energy Direct Current (DC) microgrid can be the best possible approach to tackle the power grid shortcomings and to electrify communities that are not yet covered by the power grid or communities that want to transition to clean energy. The research focuses on the design of an optimal 48 VDC Multiple-PV Standalone microgrid in remote areas not covered by the main grid. The proposed microgrid can be typically used for lighting, charging phones, and other low-power applications. The microgrid will consist of 4 microgrid subgrids, each consisting of a dedicated Solar PV array, battery storage systems, loads, and other components that connect to the DC Bus and need to be monitored and controlled for efficient operation. Furthermore, the subgrids were designed based on the meteorological data of the selected location and the load demand for each subgrid. The microgrid design enables the subgrids to share power through a bidirectional DC-DC converter based on certain conditions. A power-sharing management system was implemented to manage power-sharing ensuring that the sharing subgrid does not drive its users to load shedding. Moreover, the microgrid design was simulated on Matlab/Simulink to observe the operation of the designed system and to determine if the proposed design would be able to achieve the desired goal. The results obtained from simulations indicate that the proposed microgrid design can provide an optimal service to its users by allowing the subgrid with surplus energy to share its power with the subgrid when needed.Item An investigation into harvesting solar energy using thermoelectric generator coupled IBR sheeting(2024-05) Malik, Momina; Gilpin, Mark; Graham, Bruce RobertThere is a current global impending need for clean and renewable energy sources. Fossil fuels are non-renewable finite resources, which are dwindling because of high cost, and environmentally damaging retrieval techniques. South Africa’s coal resources may soon reach their end, which further stresses the need for green energy. An efficient and more feasible alternative is solar energy. Thermoelectric generators (TEGs) may use the energy from the sun to generate power and are an innovative means to harvest electricity. The proposed study intends to validate whether TEGs are a potential method to harvesting solar power. The study herein is a preliminary experimental investigation into a development in a TEG modular prototype. Relevant tests are run, and the performance characteristics obtained from experiments are discussed. The TEG system developed and tested in this study consists of 2 equally sized pieces of Inverted Box Rib (IBR) sheeting with one side exposed to a light source, while the other side remains shaded. An Arduino, connected and coded to read and display resulting temperatures, Peltier tiles, magnets, simple heatsinks and Multimeters are connected to measure open circuit voltage and closed-circuit current generated from the temperature difference between the two sides of the IBR sheeting. The system aims to harvest energy whilst keeping the assembly and construction simple, practical, and minimalistic. Outdoor experiments were conducted to determine the temperatures and the resultant temperature gradients the configuration may experience in operation. The data collected established parameters for the laboratory experimental setup. The laboratory experiments characterized the power output of the units. For comparative purposes, some variables were removed, such that the testing variable was isolated. Some environmental variables were removed by testing in a laboratory. The TEG was tested in the vertical position to allow for maximum natural convection, and hence may not reflect results that would be obtained in all applications. The TEG system is exposed to the light source at different distances, perpendicular to the sheets. The study intends to investigate the effect that the 2 variables have on the amount of solar power generated i.e., the colour of metal IBR sheeting, and the ideal electrical arrangement for scalability of Peltier tiles for maximum power output (𝑃𝑚𝑎𝑥). The IV curve generation method (later explained in chapter 2.4.1) is used to read the parameters required to calculate 𝑃𝑚𝑎𝑥. The results show a strong influence of the black coated sheets on the power output of the TEGs. It is deduced from solar experiments, that the aluminium rods used as the heatsink fulfilled its purpose of regulating a ∆T of 1-2°𝐶. Furthermore, the TEG in series configuration, generated the highest 𝑃𝑚𝑎𝑥 when located 300mm from the heat source, followed by 600mm and lastly, 900mm. The same pattern is found for the unit and parallel configurations. It may be concluded from the proposed TEG system that TEGs are a potential method of harvesting solar energy on IBR sheeting, specifically in a vertical position. However, applications of different orientations and geographical locations require further investigation. The results merit further investigation and refinement into the use of TEGs on IBR sheeting where the herein designed TEG system is set-up in a user friendly, simple, cost effective and practical manner for solar energy harvesting. While the power output per TEG tile is small in magnitude, the proposed configuration has potential in the coupling of multiple units to increase power output. The current work shows potential for the use of TEGs in this application. Through further investigation, refinement and cost analysis, the system may prove to be a practical method of solar energy harvesting.Item Techno-economic analysis and life cycle assessment for production of biofuels from spent coffee grounds(2024-05) Kisiga, Wilberforce; Chetty, Manimagalay; Rathilal, SudeshSpent Coffee Grounds (SCGs) are one of the most abundant agro-industrial residues generated from the coffee brewing industry and coffee espresso machines in restaurants, cafeterias, cafes and homes. It is believed that for every ton of coffee beans processed, 650 kg of SCG is left as solid residues. Coffee being the second traded commodity after petroleum, means that a lot of SCGs are generated annually and end up into landfills. Efforts are being made to turn this valuable waste into biofuels, however, most of these efforts end up at laboratory benches and few studies have focused on industrial scale production of biofuels from SCG. Six biomass-to-energy conversion technologies were compared from technical, economic and environmental perspectives: Fast pyrolysis, Hydrothermal Liquefaction (HTL), gasification, Anaerobic Digestion (AD), fermentation and biodiesel production. The processing technologies were selected because they are the most researched biomass-to-fuel conversion routes. Each of the processing routes was simulated in Aspen plus V11 using input data from literature. The mass and energy balances obtained from simulations were used to conduct Techno-Economic Analyses (TEAs) and Life Cycle Assessments (LCAs). TEA was conducted with help of Aspen Process Economic Analyzer (APEA) and Microsoft Excel spreadsheets whereas OpenLCA V1.11.0 software was employed for LCA. After the processing routes were successfully simulated, APEA was used to estimate the installed Cost of all Equipment (COE). The Capital Expenditure (CAPEX) required to build the biorefineries was then estimated basing on COE for each biorefinery. Then the Operating Expenses (OPEX) required for running the day-to-day operations of the plant were estimated as the sum of Variable Operating Expenses (VOC) and Fixed Operating Expenses (FOC). The revenues from the sales of finished products were estimated and used to calculate the gross profit. For the plant life of 25 years; using straight-line depreciation of 10% per year, discount rate of 12% and tax rate of 28%, the Discounted Cash Flow Analysis (DCFA) was used to calculate the economic indicators i.e. the Net Present Value (NPV), Profitability Index (PI), Internal Rate of Return (IRR) and Discounted Payback Period (DPBP). For LCA, the methodology outlined by the ISO 14040/44 framework was used. The method outlines four steps followed to conduct LCA i.e. goal and cope definition, Life Cycle Inventory (LCI), Life Cycle Impact Assessment (LCIA) and interpretation of results. The goal of this study was to identify the processing route with least environmental impacts and the cradle-to-gate system boundary was selected. LCI was conducted using the mass and energy balances obtained from Aspen plus simulation and the flows present in the Agribalyse Version 3 database, downloaded from OpenLCA nexus. LCIA was conducted using the ReCiPe 2016 Midpoint (H) and was also downloaded from OpenLCA nexus. Eight impact categories namely, global warming, fossil resource scarcity, particulate matter formation, terrestrial acidification, freshwater eutrophication, marine eutrophication, mineral resource scarcity and water consumption were selected. The results were analysed to identify the conversion route with less environmental effects. Results from the economic analysis showed that fast pyrolysis was the most economically profitable processing route with a NPV, PI, DPBP and IRR of 6.3 million USD, 1.85, 5.4 years and 37%, respectively. In the second position was biogas production with a NPV, PI, DPBP and IRR of 3.4 million USD, 1.65, 5.7 years and 34%, respectively. Gasification was in the third position with a NPV, PI, DPBP and IRR of 5.4 million USD, 1.48, 6.0 years and 32%, respectively. In the fourth position was biodiesel production with a NPV, PI, DPBP and IRR of 3.9 million USD, 0.86, 8.0 years and 24%, respectively. HTL was in the fifth position with a NPV, PI, DPBP and IRR of 0.68 million USD, 0.29, 13.0 years and 16%, respectively. Bioethanol production was not economically profitable as the revenues generated from sales of finished products were smaller than the operating expenses, thus no profit could be generated. Results from environmental impact assessment showed that fast pyrolysis was the most environmentally friendly processing route, followed by biogas production, biodiesel production, gasification, and bioethanol production, whereas HTL had the highest environmental impacts. Electricity consumption was the biggest contributor to the environmental impacts, making HTL, which was the highest electricity consuming processing route, to be the worst environmentally. However, biogas production was the least electricity consuming processing route but not the best environmentally due to large production of carbon dioxide and methane (biogas) from anaerobic digestion. The large production of carbon dioxide can be mitigated through using it to grow algae or in supercritical carbon dioxide extraction of lipids. However, the cost associated with additional unit processes can escalate the biogas production costs. These greenhouse gases were the biggest contributors of global warming, pushing biogas production to the second position after pyrolysis.Fast pyrolysis was proposed to be the best environmentally and economically feasible processing route for the production of biofuels from SCG.Item Feasibility analysis and optimization of new energy technologies for sustainable development(2024-05) Kumba, Hagreaves; Olanrewaju, Oludolapo AkanniEnergy is essential for crucial development in Africa. The current electricity shortages or load shedding in South Africa show the country faces significant challenges in reaching positive economic growth. For industries to operate sustainably, an innovative mechanism must be tailored to solve the negative impacts of industrial energy use, particularly climate change. Even though fossil fuels generate the majority of produced electricity in South Africa, the country’s potential for renewable energy sources is vast. In contrast, solar irradiance and wind offer considerable commercial potential. New renewable energy resources are widely seen as a means to address the challenges of climate change and energy insecurity. They can be of crucial importance in developing a sustainable economy in the country. The study aims to show how renewable energy technologies can provide new economic opportunities, contribute to higher standards of living, and reduce the impacts of society on ecosystems, among other things. This thesis presents a feasibility analysis and optimization of new energy technologies by designing and simulating a grid-connected PV system for sustainable development. The PVsyst software was used to simulate and optimize the PV system. The software was used to design and model the PV systems and to calculate the energy production, economic performance, and environmental impact. The researcher utilized simulation data to compare PV system performance in three scenarios and identify the optimal one. Overall, the findings of this thesis suggest that grid-connected PV systems are a feasible and sustainable option to meet South Africa's energy needs. By implementing the results and recommendations, the government, investors, and community can work together to develop and deploy a successful PV system that will benefit all.Item Multiscale modelling of biogas purification using montmorillonite adsorbent(2024-05) Khuzwayo, Thandeka Ntombifuthi; Ngema, Peterson Thokozani; Ramsuroop, Suresh; Lasich, Madison M.Biogas, a renewable energy source derived from organic materials, offers significant potential for creating sustainable power sources and minimize environmental pollution. However, the presence of contaminants like carbon dioxide (CO2) and hydrogen sulfide (H2S) in biogas can reduce its usefulness and efficiency in a number of applications. To address this issue, this research focuses on the purification of biogas using clay adsorbent. This study investigates the adsorption capacity of clay minerals, such as montmorillonite, in removing CO2 and H2S from biogas. In this study, Grand Canonical Monte Carlo (GCMC) simulations were performed using a self-consistent forcefield to predict adsorption isotherms for methane, carbon dioxide, ethane, and hydrogen sulfide in montmorillonite lattice. The experimental setup involved a Pressure Swing Adsorption (PSA) column, where biogas passes through the adsorbent, leading to the adsorption of impurities while maintaining the methane content, thus enhancing the overall biogas quality. The model was fitted with Langmuir adsorption isotherms for all species at different pressures and ambient temperature, coupled with batch equilibrium approach to model the PSA system. The equilibrium modelling of a pressure swing adsorption system to purify CH4/CO2 feedstock was demonstrated in such that a system can be incorporated into a solar biogas reforming process, targeting purity of 93-96 mol-% methane, which was readily achievable. The modelling of PSA indicate that the system could produce over 96% of methane and a recovery of around 82% at low pressure. The findings suggest that the choice of clay adsorbent and optimization of process parameters can significantly enhance the purification efficiency of biogas via pressure-swing adsorption. The strong selectivity of the montmorillonite adsorbent has affinity to adsorb carbon dioxide and other species at low pressures, even though nitrogen require more pressure to be adsorbed onto the montmorillonite bed.Item Kernel estimation modelling and optimization of hybrid power system for a typical South African rural area(2023-09) Magenuka, Thand’uxolo Kenneth; Kabeya, Musasa; Akindeji, Kayode TimothyTo increase the accessibility of electricity even to those rural sparsely scattered isolated rural regions, renewable energy seems to be a viable and sustainable option. Before investing in renewables in these areas, a feasibility study is of paramount importance starting with assessing and determining the amount of available solar irradiance and wind speeds for the area. In addition, a techno-economic feasibility study is of paramount importance to determine the most economical and sustainable standalone hybrid system. This research presents a study using a nonparametric kernel density estimation method to determine solar irradiance and wind speeds. In addition to this kernel determination method, the study performs a feasibility analysis using a hybrid renewable energy system that consists of two renewables with biodiesel and battery backup to supply the energy demands of a rural household in South Africa. The research commences with a literature review of several probability distribution functions (pdfs) commonly used in testing both solar irradiance and wind speeds. It established that not all sites can be defined by the same pdf and there is no science in selecting a distribution function but rather random testing of a range of functions. The parametric probability functions tested in this work are Gamma, Weibull, and Lognormal. The work then compares the performance of these parametric pdfs with the nonparametric kernel density estimation method which this study advocates for its application. In judging the performance and correctness of these pdfs, mean bias error (mbe) and root mean square error (rmse) are used as performance test criteria for the parametric probability distribution function. As for the nonparametric pdf which this research advocates for its use, an integral squared error, ISE is used for the presentation assessment with the conventional parametric normal distribution. From the results, it is observed with the proposed nonparametric kernel density estimator gives precise estimation and improved adaptableness, as opposed to the widely used conventional parametric distribution for both the use in solar irradiation and wind, speeds estimations. In addition, the research results demonstrated that the commonly used Epanechnikov and Gaussian KDE methods were the most adjustable methods for all seven tested stations. The second aspect of the study applies the tested data to design and perform a feasibility study of using a hybrid renewable energy system that consists of two renewables with biodiesel and battery backup to supply energy demands for a typical rural household. Thus, the study makes use of a simulation to design and determine an optimized hybrid renewable energy system for application in rural households. The energy resources considered for this standalone hybrid system are solar PV, wind, diesel generator, and a storage battery system. In performing the system simulation and optimization concerning economic viability, sustainability, energy efficiency, and environmental impact is carried out using the Hybrid Optimization Model for Electric Renewables (HOMER) simulation and optimization software tool. Concerning the results obtained, HOMER gave seven best-optimized systems. In breaking down the seven optimized results, four of the results were hybrid energy systems and three with only one energy resource. Moreover, from these results, three systems were pure green energy supplied and not utilizing any diesel generator (DG). The best-optimized system for this rural household consisted of PV/DG with an NPC of $ 72,720, while the system which utilized all resources available was second-ranked with an NPC of $ 79,272. The use of only renewable resources for this region was fourth-ranked with NPC of $ 86,760. The study demonstrates the feasibility and viability of having rural areas benefit from electricity access. Moreover, this study will contribute towards the strides of just energy transition envisaged by the country in solving the energy crisis currently being experienced.Item Liquid fuel production from catalytic pyrolysis of municipal plastic waste using synthesized Zeolite from Kaolin(2023-05) Olagunju, Olusegun Ayodeji; Kiambi, Sammy LewisMunicipal Plastic wastes are potential sources of alternative energy owing to their longchain hydrocarbon with high heating values. Plastic waste (PW) is the major constituent of municipal solid waste (MSW) and it is becoming one of the largest MSWs in developing countries. The accumulation of plastic wastes over a length of time in conjunction with the improper and conventional waste management strategies has led to major health and environmental hazards such as greenhouse gas emissions, groundwater pollution, and several other human health and aquatic inhabitant problems. To address the environmental problem associated with municipal plastic waste, it is necessary to explore the catalytic pyrolysis recycling method of plastic waste which is a promising method of Municipal plastic waste management. In this research four major used Municipal Plastic Wastes (MPW) namely Polystyrene (PS), Polypropylene (PP), Polyethylene (PE), and polyethylene terephthalate (PET) were investigated for the liquid-oil production individually and at mixed ratios. Three different samples of kaolin (G1, G3, and G10) obtained from Grahamstown, South Africa were used as the raw materials in the synthesis of ZSM-5 zeolite used as the catalyst. In the preparation of the kaolin-based ZSM-5, the required amount of G&W metakaolin and sodium hydroxide were dissolved in deionized (DI) water, and tetrapropylammonium bromide (TPABr) were also mixed separately with the required amount of DI water. The solution of NaOH/Kaolin and sodium silicate solution were added simultaneously to the solution of the TPABr while stirring. Nitric acid was used to control the pH until the solution mixture is homogenous. The synthesized gel was transferred to stainless steel Teflon-lined autoclave cup and was hydrothermally treated at 180 ℃ for two days. The resulting product was washed with DI until the pH is less than 8. The sample was dried overnight at 80 ℃ and calcined for 5 hours at 550 ℃. The resulting synthesized zeolites (G1/ZSM-5, G3/ZSM-5, and G10/ZSM-5) were then characterized using Fourier transforms infrared (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The catalysts produced were applied in the production of liquid fuel from Municipal waste plastics such as Polystyrene (PS), Polypropylene (PP), Polyethylene (PE), and polyethylene terephthalate (PET) under an optimized catalytic pyrolysis reaction process. The operating parameters considered were catalyst loading, reaction time, and the temperature was investigated and optimized using response surface methodology (RSM) to obtain the best operating condition for the maximum yields. The optimized conditions established from the liquid fuels produced were used as a standard for the catalytic pyrolysis process condition for the single and mixed ratios. The catalytic pyrolysis of mixed plastic wastes in different ratios was conducted with the synthesized G1/ZSM-5, G3/ZSM-5, and G10/ZSM-5 zeolite catalysts separately. All the mixtures of PP and PE produced higher liquid oil yields than the single PP or PE feedstock. Also, the highest liquid oil yield was obtained from PS/PE/PP sample with G10/ZSM-5 zeolite, and the lowest yield was from PP/PE sample with G1/ZSM-5 zeolite catalysts. The highest gases and char yields were from PP/PE and PS/PE with G1/ZSM5 zeolite catalysts. The quality, quantity, and chemical composition of the products were analyzed. The liquid oils, produced from the selected types of plastic wastes using synthesized and commercial catalysts, mainly consisted of aromatic hydrocarbons such as styrene, ethylbenzene, benzene, azulene, naphthalene, and toluene with a few aliphatic hydrocarbon compounds as confirmed by GC–MS and FT-IR analysis. The analysis showed that the liquid oils produced had high HHV (30.6–45 MJ/kg), similar to conventional diesel. The physicochemical properties of the oil produced were also compared with South African (SANS) and International standards (ASTM). The synthesis of ZSM-5 zeolite was successfully carried out from locally sourced kaolin. The characterization results revealed that the patterns of G3/ZSM-5 and G10/ZSM-5 exhibit sharp reflections (2θ 7.8, 8.8, 23.1, 23.3, 23.7, and 24.3o ) with high intensity, which shows that the synthesized zeolite are solid crystals owing to their high Si/Al ratio. These catalysts were found to be effective and active in the oil conversion of both single and mixed feedstock ratios. The process of mixing the plastic wastes was found to be a very effective approach in the catalytic pyrolysis production process as it eliminates the need for sorting these wastes. Optimizing the process also helps in establishing operating parameters that produce optimum yield. The hydrocarbon properties obtained were within the international and South African standard specifications.Item Coordinated control of conventional power sources and plug-in hybrid electric vehicles for a hybrid power system(2022-05) Adbul-Kader, Mohammed Ozayr; Akindeji, Timothy Kayode; Sharma, GulshanGlobally, the requirement for renewable and clean energy technologies is becoming vastly popular. With the high implementation of solar and wind energy systems, together with plugin hybrid electric vehicle (PHEV) aggregators, energy costs can be minimised, greenhouse gas emissions decrease, and overall maintenance becomes reduced. The constant increase of load demand is becoming a challenge for the current power systems, with difficulties including stability concerns and excessive regulations by the government. Due to irradiance and wind speed fluctuations, the solar and wind energy system’s non-linearity affects the existing power system stability. The growth of the electric vehicle industry has also shed new light on potential auxiliary services that can be provided, as and when required, to the power system. Hence, this research examines the potential control strategies that are required to maintain the system in steady-state conditions after disturbances that occur with higher penetration of renewable energy systems (RESs) and PHEVs. The case study models a isolated two-area thermal type power system that is interconnected through an AC tie-line. Three scenarios are modelled, simulated and analysed. The first scenario models a isolated thermal power system with PHEVs with two areas which utilises a fractional order proportional integral derivative (FOPID) controller in each area. The resulting model is analysed to see the effects of PHEVs coupled with FOPID on the power system. The second scenario models a isolated two-area thermal power system with RES and utilises a fuzzy type-2 (FT2) FOPID controller in each area. The RES penetration istested for its non-linearity effect on the isolated power system, and the error is reduced by an advanced controller that uses artificial intelligence techniques. The third scenario is modelled as an isolated two-area thermal power system with PHEVs and RES coupled with neural network predictive controller (NNPC) in each area. The three scenarios are simulated in MATLAB/Simulink with results displayed graphically and numerically. The results show that the integration of PHEVs for load and/or storage in the multi-area power system, and the proposed control methods for each scenario, have the best dynamic response with the least error, no oscillations and the fastest response to steady state condition.