• Energy Research

A low cost bipolar plate materials with a high fuel cell performance is important for the establishment of Proton Exchange Membrane (PEM ) fuel cells into the competitive world market. In this research, the effect of different bipolar plates material such as Aluminum (Al), Copper (Cu), and Stainless Steel (SS) of a single stack of proton exchange membrane (PEM) fuel cells was investigated both numerically and experimentally. Firstly, a three dimensional (3D) PEM fuel cell model was developed, and simulations were conducted using commercial computational fluid dynamics (CFD) ANSYS FLUENT to examine the effect of each bipolar plate materials on cell performance. Along with cell performance, significant parameters distributions like temperature, pressure, a mass fraction of hydrogen, oxygen, and water is presented. Then, an experimental study of a single cell of Al, Cu, and SS bipolar plate material was used in the verification of the numerical investigation. Finally, polarization curves of numerical and experimental results was compared for validation, and the result shows that Al serpentine bipolar plate material performed better than Cu and SS materials. The outcome of the investigation was in tandem to the fact that due to adsorption on metal surfaces, hydrogen molecules is more stable on Al surface than Cu and SS surfaces.

Heat transfer operations are very common in the process industry to transfer a huge amount of thermal energy, i.e., heat, from one fluid to another for different purposes. Many fluids are used as heat transfer fluid (HTF), in which water is the most common HTF due to its high specific heat, availability, and affordability. However, conventional HTFs, including water, have a lower thermal conductivity, which is the most critical thermophysical property, hence decreased heat transfer efficiency. The addition of solid particles of highly thermally conductive material, specifically at nano-size, i.e., nanoparticles NPs, result in nanofluid NF, which has evolved over the last two decades as efficient HTF and have been investigated in a wide range of applications. Among NPs, graphene (Gr) based materials have shown very high potential as NF due to the very high thermal conductivity up to 5,000 W/m.K, hence higher thermal conductivity NF. This work aims to thoroughly discuss the thermophysical properties of Gr-based NFs, including thermal conductivity, heat capacity, density, and viscosity. The discussion focus on the thermophysical properties as it is the ultimate determinator of the heat transfer characteristics of the HTF, such as the convective and the overall heat transfer coefficient as well as the heat transfer capacity of the NF. The discussion expands to the relative enhancement in such thermophysical properties reaching up to a 40% increase in thermal conductivity, as the most critical thermophysical property. The discussion shows that Gr-based NF has a much higher thermal conductivity relative to widely studied metal oxide NF and at much lower content, and lower density and viscosity increase, which is critical for determining the pumping power requirements. Critical challenges facing the application of Gr-based NFs such as cost, stability, increased density and viscosity, and environmental impacts are thoroughly discussed with mitigation recommendations given.

L'industrie des pâtes et papiers est une technologie à forte intensité d'énergie. Une grande attention à la réduction de sa propre consommation d'énergie et à la diminution du gaspillage d'énergie disponible devrait donc être consacrée. Dans la présente enquête, l'approche énergie-ergie d'une entreprise de pâtes et papiers intégrée à une récupération chimique de liqueur noire (LN) et de soude est étudiée en fait pendant un an. Le système de récupération chimique BL qui présente les principaux avantages pour éviter la pollution de l'environnement en brûlant les déchets organiques et en recyclant la soude est également étudié de manière approfondie. Le gaz naturel (GN) et le BL sont utilisés dans la chaudière électrique (PB) et la chaudière de récupération (RB), respectivement. De plus, dans la présente mise en œuvre, les réactions chimiques du GN et du BL sont présentées. Les résultats obtenus montrent que les pourcentages de pertes d'énergie dans le condenseur, le RB, les évaporateurs et le PB sont de 49,16, 19,28, 14,22 et 3,96 %, respectivement. Les valeurs moyennes des pourcentages de destruction d'exergie dans RB et PB tout au long de l'année sont respectivement de 41,63 et 33,5 %. L'efficacité énergétique globale maximale du système est de 32,09 % à une température ambiante de 290 K, tandis que l'efficacité énergétique du système est de 53,7 %. La industria de la celulosa y el papel es una tecnología que consume mucha energía, por lo que se debe dedicar gran atención a reducir su propio consumo de energía y disminuir el desperdicio de energía disponible. En la presente investigación se estudia durante un año el enfoque energía-energía de una empresa de celulosa y papel integrada con una recuperación química de licor negro (BL) y sosa. También se investiga exhaustivamente el sistema de recuperación de BL químico que tiene los beneficios principales para evitar la contaminación ambiental al quemar desechos orgánicos y reciclar la soda. El gas natural (GN) y el BL se utilizan en calderas eléctricas (PB) y calderas de recuperación (RB), respectivamente. Además, en la presente implementación, se presentan las reacciones químicas de NG y BL. Los resultados obtenidos muestran que los porcentajes de pérdidas de energía en el condensador, RB, evaporadores y PB son 49.16, 19.28, 14.22 y 3.96%, respectivamente. Los valores medios de los porcentajes de destrucción de exergía en RB y PB alrededor del año son 41,63 y 33,5%, respectivamente. La eficiencia energética global máxima del sistema es del 32,09% a una temperatura ambiente de 290 K, mientras que la eficiencia energética del sistema es del 53,7%. The pulp and paper industry is a power-intensive technology so great attention to reducing its own energy consumption and declining the waste of available energy should be devoted. In the current investigation, the energy-exergy approach of a pulp and paper company integrated with a chemical recovery of black liquor (BL) and soda is studied actually for one year. The chemical BL recovery system that has the primary benefits to avoid environmental pollution by burning organic waste and recycling the soda is also comprehensively investigated. Natural gas (NG) and BL are utilized in power boiler (PB) and recovery boiler (RB), respectively. Moreover, in the present implementation, the chemical reactions of NG and BL are presented. The obtained results show that the percentages of energy losses in the condenser, RB, evaporators, and PB are 49.16, 19.28, 14.22, and 3.96%, respectively. The average values of exergy destruction percentages in RB and PB around the year are 41.63 and 33.5%, respectively. The maximum system overall exergy efficiency is 32.09% at an environment temperature of 290 K, whereas the energy efficiency of the system is 53.7%. صناعة اللب والورق هي تقنية كثيفة الاستخدام للطاقة، لذا يجب تكريس اهتمام كبير لتقليل استهلاكها للطاقة وتقليل هدر الطاقة المتاحة. في التحقيق الحالي، تتم دراسة نهج الطاقة والطاقة لشركة لب الورق والورق المدمجة مع الاسترداد الكيميائي للكحول الأسود (BL) والصودا في الواقع لمدة عام واحد. كما يتم التحقيق بشكل شامل في نظام استرداد BL الكيميائي الذي له فوائد أساسية لتجنب التلوث البيئي عن طريق حرق النفايات العضوية وإعادة تدوير الصودا. يتم استخدام الغاز الطبيعي (NG) و BL في مرجل الطاقة (PB) ومرجل الاسترداد (RB)، على التوالي. علاوة على ذلك، في التنفيذ الحالي، يتم عرض التفاعلات الكيميائية للغاز الطبيعي و BL. تظهر النتائج التي تم الحصول عليها أن النسب المئوية لفقدان الطاقة في المكثف و RB والمبخرات و PB هي 49.16 و 19.28 و 14.22 و 3.96 ٪ على التوالي. يبلغ متوسط قيم نسب تدمير الطاقة الخارجية في الميزانية العادية والميزانية البرنامجية على مدار العام 41.63 و 33.5 ٪ على التوالي. الحد الأقصى لكفاءة الطاقة الكلية للنظام هو 32.09 ٪ عند درجة حرارة بيئة تبلغ 290 كلفن، في حين أن كفاءة الطاقة للنظام هي 53.7 ٪.

Metaheuristic optimization algorithms (MHA) play a significant role in obtaining the best (optimal) values of the system’s parameters to improve its performance. This role is significantly apparent when dealing with systems where the classical analytical methods fail. Fractional-order (FO) systems have not yet shown an easy procedure to deal with the determination of their optimal parameters through traditional methods. In this paper, a recent, systematic. And comprehensive review is presented to highlight the role of MHA in obtaining the best set of gains and orders for FO controllers. The systematic review starts by exploring the most relevant publications related to the MHA and the FO controllers. The study is focused on the most popular controllers such as the FO-PI, FO-PID, FO Type-1 fuzzy-PID, and FO Type-2 fuzzy-PID. The time domain is restricted in the articles published through the last decade (2014:2023) in the most reputed databases such as Scopus, Web of Science, Science Direct, and Google Scholar. The identified number of papers, from the entire databases, has reached 850 articles. A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was applied to the initial set of articles to be screened and filtered to end up with a final list that contains 82 articles. Then, a thorough and comprehensive study was applied to the final list. The results showed that Particle Swarm Optimization (PSO) is the most attractive optimizer to the researchers to be used in the optimal parameters identification of the FO controllers as it attains about 25% of the published papers. In addition, the papers that used PSO as an optimizer have gained a high citation number despite the fact that the Chaotic Atom Search Optimization (ChASO) is the highest one, but it is used only once. Furthermore, the Integral of the Time-Weighted Absolute Error (ITAE) is the best nominated cost function. Based on our comprehensive literature review, this appears to be the first review paper that systematically and comprehensively addresses the optimization of the parameters of the fractional-order PI, PID, Type-1, and Type-2 fuzzy controllers with the use of MHAs. Therefore, the work in this paper can be used as a guide for researchers who are interested in working in this field.

Abstract The rapid progress in the global population and technical advances have resulted in exponential growth in the use of fossil fuels. These are not only limited in resources but also have a severe environmental impact. The accumulation of greenhouse gases (GHGs), more specifically carbon emissions, in the environment has resulted in severe health issues and climate changes. The Paris Climate Agreement calls for restricting global warming to only 1.5 °C by 2050 relative to the pre-industrial era. This requires reducing global GHGs emissions as soon and as much as possible. Massive efforts are being put into minimizing GHG emissions, such as using renewable energy resources and/or using carbon capture technologies (CCT). In this study, different CCTs were introduced, focusing on the pre-combustion as a promising CCT approach. In this work, the role of CCT in realizing the United Nations Sustainable Development Goals (SDGs) was thoroughly analyzed and discussed. A total of 87 indicators were developed to measure and analyze the contribution of CCT to achieving the different SDGs. The focus given to the role of the pre-combustion CCT in achieving SDGs is being elaborated. The indicators and analysis covered the economic, environmental, and social pillars of sustainable development. It was found that CCT contributes well to all 17 SDGs, with core and substantial contributions to SDG-7 of "Affordable and clean energy", and ultimately SDG-13 of "Climate action". The developed indicators would work as a guideline for the different players to ensure that CCT is fully adhering the SDGs principles. The proposed indicators have nine main benefits, i.e., assist in the achievement of the SDGs, providing information for the decision-makers, enhance and benchmark sustainability performance, improve risk management, enhance data management and reporting practices, improve resource allocation and reduce the expenses, improve environmental performance, reduce social impact, and improve communications with stakeholder. Moreover, the different barriers facing the CCT were presented.

Living organisms' energy conversion is considered as an essential and sustainable green energy source and future bio-hybrid technologies. Recently, plants were used after harvesting as biomass in bio-fermentation as an energy source. In bio-electrochemical systems, microorganisms work with plants to generate electricity, hydrogen, or methane. This work discusses the simultaneous pollutant removal and electricity generation in plant-based bio-electrochemical systems (P-BES). Factors affecting the P-BES performance and the removal efficiencies of the different organic and inorganic pollutants were illustrated. Furthermore, the plant-based bioelectrochemical systems' role in achieving the sustainable development goals (SDGs) was discussed. The SDGs contribution of plant-based bioelectrochemical systems were presented and discussed to evaluate such systems' ability to achieve the three pillars of sustainable development, i.e., economic, environmental, and social.

The sudden increase in the concentration of carbon dioxide (CO2) in the atmosphere due to the high dependency on fossil products has created the need for an urgent solution to mitigate this challenge. Global warming, which is a direct result of excessive CO2 emissions into the atmosphere, is one major issue that the world is trying to curb, especially in the 21st Century where most energy generation mediums operate using fossil products. This investigation considered a number of materials ideal for the capturing of CO2 in the post-combustion process. The application of aqueous ammonia, amine solutions, ionic liquids, and activated carbons is thoroughly discussed. Notable challenges are impeding their advancement, which are clearly expatiated in the report. Some merits and demerits of these technologies are also presented. Future research directions for each of these technologies are also analyzed and explained in detail. Furthermore, the impact of post-combustion CO2 capture on the circular economy is also presented.