Mining activities often leave behind a legacy of environmental challenges, with aging tailings ponds representing a significant concern due to their potential for leachate formation and subsequent contaminant release. Thus, this study employs Electrical Resistivity Tomography (ERT) to investigate the intricate pathways of leachate within an aging mining tailings pond, addressing the pressing environmental and human health concerns associated with potential contaminant release. Ten 2D ERT profiles were acquired at the El Mochito mine waste site, covering an area of approximately half a square kilometer. These profiles, ranging in length from 104 to 363 m, provided insights into subsurface conditions down to a maximum depth of 60 m. The subsurface mapping of the ERT data showed three different geoelectric layers. The uppermost layer, with a thickness of approximately 2.5 m and resistivity values ranging from 60 to 100 Ohm.m, was identified as a dry tailing/soil zone. Beneath it, the second layer exhibited moderately resistive values (30–60 Ohm.m) with varying thicknesses of 10–20 m, signifying a percolation/leaching zone (semi-saturated zone). The third layer, characterized by substantially low resistivity (1–30 Ohm.m), indicated saturation and the presence of conductive materials, strongly suggesting active leaching. Based on these findings, this study recommends further investigation through geochemical analysis of subsurface samples and more advanced geophysical imaging techniques to validate the distribution of anomalous zones and delineate remediation pathways. This study lays the foundation for future comprehensive research that will integrate geophysical surveys with geochemical analysis and establish 4D modeling techniques to monitor pollutant penetration over time, with a particular focus on mine waste tailings mapping. Plus, this study contributes valuable insights into the characterization of leachate pathways within mining tailings ponds, offering a foundation for informed environmental management and remediation strategies.
The accurate characterization and mapping of low-grade ore deposits necessitate the utilization of a robust exploration technique. Induced polarization (IP) tomography is a powerful geophysical method for mineral exploration. An integrated survey using electrical resistivity tomography (ERT) and IP was employed in this study to characterize and map (Zn-Pb-Ag) ore deposits in NE New Brunswick, Canada. The survey encompassed twelve parallel lines across the study area. The 2D and 3D inversion of the results provided a detailed image of the resistivity and chargeability ranges of subsurface formations. The boundaries of sulfide mineralization were determined based on resistivity values of (700–2000 Ohm.m) and chargeability values of (3.5 mV/V) and were found to be located at an approximate depth of 80–150 m from the surface. The findings were validated through a comparison with data from borehole logs and mineralogy data analysis. The size and shape of sulfide deposits were successfully characterized and mapped in the study area using this cost-effective mapping approach.
Over the last two decades, extensive research has focused on enhancing operational efficiency, emission reduction, and technological advancements in combined cycle power plants. This study conducts a comprehensive bibliometric analysis encompassing over 4100 peer-reviewed publications within the Scopus database (2000–2022) related to combined cycle power plants. The outcomes reveal a burgeoning global research landscape, primarily led by the United States, China, Italy, and the United Kingdom. Encompassing diverse domains such as engineering, energy, environment, and others, this research delves into technical areas like carbon capture, exergy analysis, and optimization, while hinting at emerging research directions involving machine learning and power-to-gas technologies. Renowned authors such as Bolland, Tsatsaronis, and Dincer, alongside influential institutions like Tsinghua University and the Norwegian University of Science and Technology, form significant research networks. International collaboration underscores widespread knowledge exchange, with the United States and China leading in total citations, while Italy boasts the highest average citations per article. A comprehensive analysis of keywords underscores the interdisciplinary nature of research, spanning technical, economic, and environmental dimensions. Further affirmation is found in the extensive publication span across general energy and specialized thermoscience journals. This study offers a comprehensive overview of research productivity, impact, and trends in combined cycle power plant research over the past two decades, providing actionable insights for strategic research planning and global performance enhancement.
As the demand for energy continues to rise, it becomes increasingly crucial to explore new energy resources and enhance the efficiency of existing ones. Combined Cycle Power Plants (CCPPs) play a pivotal role in improving efficiency and electricity generation. However, conducting a comprehensive performance analysis is essential to maintain optimal operating conditions. This paper presents a case study involving energy and exergy analyses of a 750 MW CCPP located in Assiut, Egypt. The study's primary objective is to assess the energy efficiency of the plant and identify opportunities for enhancement. The findings indicate that the combustion chambers are the primary contributors to exergy destruction, accounting for 53.3% of the total exergy loss, followed by heat recovery steam generators (HRSGs) at 32%, compressors at 5.3%, steam turbines at 5%, gas turbines at 2.3%, and cooling systems at 1.7%. Additionally, the research highlights that the energy and exergy efficiencies for the entire plant stand at 33.5% and 34.6%, respectively.
This study demonstrates the potential of exergy analysis as a tool for identifying inefficiencies within complex systems and prioritizing improvements. Specifically targeting the most inefficient components can lead to the greatest gains in overall system efficiency. To illustrate this point, the authors conducted an energy and exergy assessment of a gas turbine power plant located in Assiut, Egypt. The results revealed that the combustion chamber was the primary source of exergy destruction, indicating that this component has the greatest potential for improvement. The gas turbine was found to have the highest exergy efficiency at 95.3%, followed by the air compressor at 87.4%, while the combustion chamber had an exergy efficiency of 71.2%. The overall energy and exergy efficiency of the system were 28.8% and 27.17%, respectively. The study also highlights the impact of ambient temperature on efficiency and losses, with higher temperatures leading to reduced efficiency and increased exergy destruction. This underscores the need for optimization strategies to mitigate the impact of ambient temperature and maximize plant performance.
Thermal power plants are pivotal in meeting global energy demands, yet enhancing their efficiency and sustainability remains an enduring challenge. While previous studies have scrutinized energy and exergy analyses of distinct plant components, there's a scarcity of comprehensive reviews integrating findings across diverse plant types. This paper bridges this gap by presenting a comprehensive synthesis of recent advancements in energy and exergy studies across coal, gas, biomass, oil, and combined cycle plants. The review focuses on critical aspects: optimizing operations through modeling and advanced controls, economic evaluations encompassing costs and revenue, and assessing environmental impacts such as emissions and water use. Achieving a balance between performance, cost-effectiveness, and environmental responsibility is crucial for sustainable thermal power generation worldwide. It requires an integrated approach that considers technical, economic, and environmental factors to ensure efficiency, profitability, and minimal adverse effects on health and climate. Key findings emphasize that, in most cases, the boiler emerges as the primary source of exergy destruction, accounting for over 50% of losses across varied plant configurations. Turbines and condensers also significantly contribute to energy losses. Supercritical and ultra-supercritical power plants exhibit higher efficiencies compared to subcritical counterparts. Integrating waste-to-energy technologies with coal plants holds promise, offering efficiency improvements and reduced environmental impact. Optimizing parameters such as pressure and temperature, along with component advancements, shows potential in curbing losses. These optimization endeavors have showcased a notable up to 6% enhancement in exergy efficiency. This review underscores the critical role of ongoing thermodynamic modeling and assessments in steering towards more sustainable thermal power generation. In summary, this paper delivers valuable insights into performance benchmarks and delineates effective strategies for augmenting thermal power plant efficiency through exhaustive energy and exergy analyses.
As global energy demand continues to rise, the imperative to explore and enhance energy generation from existing resources intensifies. Combined cycle power plants (CCPPs) have emerged as a promising solution to improve efficiency and electricity production. In this study, we present a comprehensive analysis of the thermodynamic performance of a 750 MW CCPP located in Assiut, Egypt, with a focus on its energy and exergy efficiency. Our investigation reveals critical insights into the CCPP's operational dynamics. Notably, the combustion chambers emerge as the primary contributors to exergy destruction, accounting for 53.3 % of the total exergy loss. Heat recovery steam generators (HRSGs) follow closely at 32 %, while compressors, steam turbines, gas turbines, and cooling systems contribute 5.3 %, 5 %, 2.3 %, and 1.7 %, respectively. These findings pinpoint specific areas where exergy losses are most significant, offering valuable guidance for targeted improvements in CCPP performance. Furthermore, we report that the overall energy efficiency of the entire plant stands at 34.6 %, with an exergy efficiency of 33.5 %. In summary, our study provides a comprehensive scientific assessment of the thermodynamic performance of a 750 MW CCPP. The specific insights into exergy destruction and efficiency metrics not only contribute to our understanding of CCPPs but also offer actionable recommendations for optimizing the operation of gas turbine based CCPPs. These findings hold significance in the broader context of energy sustainability and environmental considerations.
The rapid increase in computing power has facilitated the use of computational fluid dynamics (CFD) as an attractive tool for simulating solar systems. As a result, researchers have conducted numerous experimental and numerical studies on solar technologies, with an increasing emphasis on the utilization of CFD for simulation purposes. Hence, this article is intended to be the first of a two-part assessment of recent improvements in the use of ANSYS-Fluent CFD simulation in solar systems. In this part, the article aims to provide a comprehensive overview of CFD simulations, using ANSYS-Fluent, for different solar systems without concentrators, including solar thermal systems, hybrid photovoltaic/thermal (PV/T) systems, and photovoltaic/phase change material (PV/PCM) systems, while the concentrating solar systems are covered in the second part. Further, this review study includes informative data about the simulations, including the considered assumptions, models, and solution methods that were used with different cooling fluids, PCM materials, absorber designs, and innovative system designs. The present assessment also highlights the results and some remarks that show different important additional information such as the applied radiation and melting/solidification models. Besides, validation techniques and errors between the experimental work and simulations are introduced. In general, the ANSYS-Fluent CFD results were validated and it was possible to optimize many design parameters with minimal effort and expense. Recent research indicated that nanofluids could be a better alternative to conventional fluids to improve the thermal functionality of flat plate and hybrid PV/T systems. Effective cooling mechanisms could reduce PV panel temperature by 15–20%. Besides, integrating PCM with PV systems could enhance efficiency by 33–46% on summer days. Incorporating different nanomaterials and using fined PV/PCM configurations, the PV/PCM system demonstrated improved cost-effectiveness, while a foam layer outside the PCM could extend PV thermal management time by 55%. Many other conclusions about the commonly used physical models, solution methods, and assumptions dealing with different systems are highlighted inside. The article also identifies additional research proposals and challenges that must be addressed to advance the study of this topic.
The energy and exergy evaluation of simple gas turbine (SGT), gas turbine with air bottoming cycle (GT-ABC), and partial oxidation gas turbine (POGT) are studied. The governing equations for each cycle are solved using energy equation Solver (EES) software. The characteristics performance for selected cycles are discussed and verified with that obtained for available practical cycles (SGT, GT-ABC, POGT). The present results show a good agreement with the practical one. The effects of significant operational parameters, turbine inlet temperature (TIT), compression ratio (CR), and compressor inlet temperature (CIT), on the specific fuel consumption, energy and exergy efficiencies are discussed. According to the findings, a reduction in CIT and a rise in TIT and CR led to enhance energy and exergy efficiency for each configuration with different ranges. Results revealed that the GT-ABC and POGT cycles are more efficient than those of SGT at the same operational parameters. The energy and exergy efficiencies are 38.4%, 36.2% for SGT, 40%, 37.8 % for GT-ABC, and 41.6%, 39.3% for POGT. The POGT cycle has a better energy and exergy performance at a lower pressure ratio than the SGT and GT-ABC.