Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 3Citation - Scopus: 3CFD-DEM Modeling of Biomass Pyrolysis in a DBD Plasma Fluidized Bed(Pergamon-Elsevier Science Ltd, 2025) Eslami, Ali; Kazemi, Saman; Hamidani, Golnaz; Zarghami, Reza; Mostoufi, NavidThis study developed a CFD-DEM model to simulate biomass pyrolysis within a dielectric barrier discharge (DBD) plasma fluidized bed reactor. Biomass, as a renewable energy source, offers a promising alternative for hydrogen production through pyrolysis. The integration of non-thermal plasma technology and fluidized bed reactors is expected to enhance conversion. Key operational parameters such as inlet gas velocity, particle size, and input voltage were examined to evaluate their effects on temperature distribution, particle conversion, and hydrogen production. Results indicated that higher inlet gas velocities promote better particle mixing and more uniform temperature and conversion distribution. Smaller particle sizes significantly enhance biomass conversion by increasing the available surface area between fluid and particles. Specifically, particles with diameters of 0.85, 1.2, and 1.5 mm achieved conversions of 10.4, 8.99, and 8.57 %, respectively, at 20 s from the start of the process. Additionally, increasing the input voltage increases the mean temperatures of particles and fluid, which enhances reaction rates and conversion. Optimizing these parameters can improve the efficiency of DBD plasmaassisted biomass pyrolysis, providing valuable insights for sustainable hydrogen production.Article Citation - WoS: 3Citation - Scopus: 1Enhancing Biomass Pyrolysis via Microwave Heating: A CFD-DEM Study on Intensification in Fluidized Beds(Elsevier Sci Ltd, 2026) Hamidani, Golnaz; Kazemi, Saman; Eslami, Ali; Zarghami, Reza; Sotudeh-Gharebagh, Rahmat; Mostoufi, NavidBiomass conversion into high-value products in fluidized beds can be significantly improved by utilizing microwave irradiation as the heating source. The present work studied microwave-assisted biomass pyrolysis using a coupled CFD-DEM model in a fluidized bed. The effect of key operating parameters, including inlet gas velocity (1.5, 2, and 2.5 times the minimum fluidization velocity), mean particle diameter (1.2, 1.3, and 1.5 mm), and microwave power input (200, 400, and 600 W), was evaluated on the performance of the reactor. The results revealed that higher microwave power increased the mean particle temperature and chemical conversion rate due to greater internal energy generation within the biomass particles. Increasing the gas velocity led to lower particle temperature because of enhanced convective heat transfer to the gas phase, and improved the uniformity of temperature and conversion distributions. Furthermore, decreasing the mean particle diameter from 1.5 to 1.2 mm increased the average temperature, from 890 to 987 K, and raised biomass conversion from 14.8 to 18.1 %, mainly by reducing convective heat losses. The validated model developed in this study enables accurate predictions of process behavior and provides valuable insights for optimizing microwave-assisted biomass pyrolysis in fluidized beds. These findings highlight the potential of microwave-assisted fluidized bed pyrolysis as an efficient technique for process intensification in producing valuable bio-based products.Review Citation - Scopus: 5A Comparative Evaluation of Dark Fermentative Bioreactor Configurations for Enhanced Hydrogen Production(Springer, 2025) Gören, Ayşegül Yağmur; Dincer, I.; Khalvati, A.Energy from renewable resources has been growing in popularity, which ultimately helps reduce emissions of greenhouse gases (GHGs) and contaminants. Since hydrogen (H2) has a higher combustion production of energy than hydrocarbon fuels, it has been identified as a clean, sustainable, and environmentally friendly energy source. There are several benefits to producing biohydrogen (bioH2) from renewable sources, including lower cost and increased sustainability. Among the bioH2 production processes, dark fermentation supports commercialization and scale-up for industrial applications. This paper considers the various bioreactors, such as anaerobic sequencing batch, continuous stirred, up-flow, fixed-bed, and membrane reactors, and their operational approaches for bioH2 production. This review paper also performs the bibliometric analysis method to identify historical and current developments in a particular field of reactor configuration studies. Furthermore, the main variables influencing reactor performance and methods for increasing process efficiency considering economic and environmental aspects are addressed. The results revealed that continuously stirred reactors are widely utilized for bioH2 production as a cost-effective reactor configuration. Moreover, the membrane bioreactors and fixed-bed reactors are yielded higher bioH2 performance than other configurations. Nevertheless, high energy consumption and costs have presented the need for further development of reactors. Consequently, future recommendations to solve the critical problems faced in reactor configurations, the gaps in the literature, and the points that need improvement were comprehensively reported. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.Book Part Citation - Scopus: 3Future Trends of Hybrid Energy Systems(Elsevier, 2024) Taheri, M.H.; Seiiedhoseiny, M.; Mohammadpourfard, M.; Akkurt, G.G.Hybrid energy systems can be defined as a combination of at least two fuel sources or energy conversion equipment that, when combined, can eliminate the constraints related to every single component. In addition to the application of multiple renewable energy sources, the improvement of energy efficiency via multi-generation plants constitutes a significant share of the recent investigations, which would include a prominent part of the future trend in hybrid energy systems. The present chapter will review the pioneer works and tries to address the future of hybrid energy systems. © 2024 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.Book Part Citation - Scopus: 1Biomass-Based Polygeneration Systems With Hydrogen Production: a Concise Review and Case Study(Springer Science and Business Media Deutschland GmbH, 2024) Hajimohammadi Tabriz,Z.; Mohammadpourfard,M.; Gökçen Akkurt,G.; Çağlar,B.This chapter discusses the importance of biomass-based polygeneration systems in producing hydrogen as a clean and safe energy carrier. The benefits of polygeneration systems, which can produce multiple products and minimize waste, are highlighted, and the need for clean and efficient hydrogen production is emphasized. This study gives a brief overview of hydrogen production from biomass-based polygeneration systems, which examines the systems in two main classifications: systems that use biomass as a potential and rich source of hydrogen and systems that exploit the energy content of biomass to run hydrogen production units. Furthermore, a new multigeneration system with hydrogen production has been introduced and thermodynamically evaluated. Also, its results have been obtained in a real situation. Overall, this chapter offers insights into the potential of biomass-based polygeneration systems in meeting energy demands while reducing environmental impact. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.Article Citation - WoS: 14Citation - Scopus: 17Cleaner Production of Biohydrogen Using Poplar Leaves: Experimental and Optimization Studies(Elsevier Sci Ltd, 2024) Goren, A. Yagmur; Kenez, Muratcan; Dincer, Ibrahim; Khalvati, AliBiohydrogen (bioH2) is recognized as a potential carbon-neutral energy vector, and developing novel methods has received increasing attention with a prime goal of producing H2 more efficient and cost effective manner. This study aimed to develop a unique reactor to investigate dark fermentative H2 production from poplar biomass using commercially available and inexpensive microorganism cultures. Therefore, six factors of the Box-Behnken design (BBD) were performed to evaluate the individual and combined effects of operational param-eters: acid concentration (2-10%), biomass concentration (2-10 g), initial pH (5-8), temperature (30-40 degrees C), mixing ratio (150-350 rpm), and microorganism concentration (2-6 g) on bioH2 production. Among the oper-ational parameters, the acid concentration was the most effective parameter on bioH2 production. The bioH2 production increased from 11.33 to 18.15 mg/g biomass with increasing acid concentration from 6 to 10%. Moreover, the optimum levels of operational variables were as follows: acid concentration of 9.9%, biomass amount of 2 g, pH of 6.56, temperature of 35 degrees C, mixing ratio of 345 rpm, and microorganism amount of 4.5 g for the highest bioH2 production of 20 mg/g-biomass according to the experimental design. Consequently, the bioH2 production performance of the dark fermentation process showed that bioH2 production from poplar biomass using commercially available microorganisms had a competitive advantage.Article Citation - WoS: 4Citation - Scopus: 5Breakthrough Curve Analysis of Phosphorylated Hazelnut Shell Waste in Column Operation for Continuous Harvesting of Lithium From Water(Elsevier, 2024) Recepoğlu, Yaşar Kemal; Arar, Ozguer; Yuksel, AsliIn batch-scale operations, biosorption employing phosphorylated hazelnut shell waste (FHS) revealed excellent lithium removal and recovery efficiency. Scaling up and implementing packed bed column systems necessitates further design and performance optimization. Lithium biosorption via FHS was investigated utilizing a continuous-flow packed-bed column operated under various flow rates and bed heights to remove Li to ultra-low levels and recover it. The Li biosorption capacity of the FHS column was unaffected by the bed height, however, when the flow rate was increased, the capacity of the FHS column decreased. The breakthrough time, exhaustion time, and uptake capacity of the column bed increased with increasing column bed height, whereas they decreased with increasing influent flow rate. At flow rates of 0.25, 0.5, and 1.0 mL/min, bed volumes (BVs, mL solution/mL biosorbent) at the breakthrough point were found to be 477, 369, and 347, respectively, with the required BVs for total saturation point of 941, 911, and 829, while the total capacity was calculated as 22.29, 20.07, and 17.69 mg Li/g sorbent. In the 1.0, 1.5, and 2.0 cm height columns filled with FHS, the breakthrough times were 282, 366, and 433 min, respectively, whereas the periods required for saturation were 781, 897, and 1033 min. The three conventional breakthrough models of the Thomas, Yoon-Nelson, and Modified Dose-Response (MDR) were used to properly estimate the whole breakthrough behavior of the FHS column and the characteristic model parameters. Li's extremely favorable separation utilizing FHS was evidenced by the steep S-shape of the breakthrough curves for both parameters flow rate and bed height. The reusability of FHS was demonstrated by operating the packed bed column in multi-cycle mode, with no appreciable loss in column performance.Article Citation - WoS: 25Citation - Scopus: 26Phosphorylated Hazelnut Shell Waste for Sustainable Lithium Recovery Application as Biosorbent(Springer, 2021) Recepoğlu, Yaşar Kemal; Yüksel, AslıHazelnut shell waste was phosphorylated to develop a novel biosorbent based on natural renewable resource for the recovery of lithium from aqueous solution. For the synthesized biosorbent, the surface morphology and mapping by SEM-EDS, chemical properties by FTIR, elemental analysis by XPS, specific surface area by BET, crystallinity by XRD and thermal properties by TGA were elucidated elaborately. The influence of biosorbent dosage, initial concentration, temperature, contact time, pH and coexisting ions were investigated. The equilibrium sorption capacity reached 6.03 mg/g under optimal conditions (i.e., biosorbent dosage of 12.0 g/L, initial Li concentration of 100 mg/L, pH value of 5.8, sorption temperature of 25 degrees C, and sorption time of 6 min). According to the sorption behavior of the phosphorylated hazelnut shell waste the Freundlich model proved to be more suitable than the Langmuir model indicating maximum sorption capacity as 7.71 mg/g at 25 degrees C. Thermodynamic parameters obtained by different isokinetic temperatures disclosed that the ion exchange reaction was feasible, spontaneous, and exothermic where the interaction between biosorbent surface and solvent plays an important role. A preliminary test on the Li recovery from geothermal water was also performed to check its applicability in a real brine. Desorption studies at 25 degrees C revealed that relatively higher desorption efficiency and capacity were achieved at 97.4% and 5.93 mg/g, respectively with a 1.0 M H2SO4 among other regenerants (i.e., HCl and NaCl). Concentrations of Li and the other cations were determined via ICP-OES. Due to such outstanding features, the novel phosphorylated hazelnut shell waste had great potential for lithium recovery from aqueous solution by being added value as a waste and recovering a strategic element of modern life simultaneously. [GRAPHICS] .