WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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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.Article Citation - WoS: 1Citation - Scopus: 1Co-Pyrolysis of Waste Wind Turbine Blades in a Molten Polyolefin Medium(Elsevier, 2025) Ekici, Ecrin; Yildiz, Magdalena Joka; Kalinowska, Monika; Wang, Jiawei; Yildiz, GurayThis study investigates the pyrolysis and co-pyrolysis processes of waste wind turbine blades (WWTB) and polyolefins (POs) at 450 degrees C in a round bottom tank reactor. The study contains three experimental sets: 1) batch pyrolysis of POs; 2) continuous pyrolysis of WWTB; 3) continuous feeding of WWTB into a molten PO medium, which was previously fed to the round bottom tank reactor batch-wise. Individual WWTB pyrolysis yields a modest 18.7 wt% of liquid, predominantly influenced by elevated ash and fixed carbon content. Conversely, copyrolysis demonstrates positive synergies, with escalating polyolefin content boosting liquid yields, reaching a peak at 61.5 wt% with a WWTB:POs mixture (25:75, wt%), while concurrently suppressing gas production to 21.6 wt%. The primary chemical groups found in the liquid obtained from WWTB are phenol and phenolic compounds, with their abundance diminishing as the POs ratio in feedstocks increases. Analysis of noncondensable gases from WWTB reveals that approximately 57.7 wt% are oxygen-containing, predominantly CO and CO2. Co-pyrolysis with POs at a 25:75 (wt%) ratio yields 47.1 wt% C3H6, resembling POs pyrolysis. The resulting solid products are rich in carbon and contains high ash. This research not only offers a detailed product analysis of WWTB but also sheds light on the dynamics of its co-pyrolysis with POs. Doing so contributes crucial insights into the transformative potential of pyrolysis and co-pyrolysis processes, covering the way for sustainable waste-to-resource solutions.Article Citation - WoS: 52Citation - Scopus: 60Applied Machine Learning for Prediction of Waste Plastic Pyrolysis Towards Valuable Fuel and Chemicals Production(Elsevier, 2023) Cheng, Yi; Yang, Yang; Coward, Brad; Wang, Jiawei; Yıldız, Güray; Ekici, Ecrin; Yıldız, GürayPyrolysis is a suitable conversion technology to address the severe ecological and environmental hurdles caused by waste plastics' ineffective pre- and/or post-user management and massive landfilling. By using machine learning (ML) algorithms, the present study developed models for predicting the products of continuous and non-catalytically processes for the pyrolysis of waste plastics. Along with different input datasets, four algorithms, including decision tree (DT), artificial neuron network (ANN), support vector machine (SVM), and Gaussian process (GP), were compared to select input variables for the most accurate models. Among these algorithms, the DT model exhibited generalisable and satisfactory accuracy (R2 > 0.99) with training data. The dataset with the elemental composition of waste plastics achieved better accuracy than that with the plastic-type for predicting liquid yields. These observations allow the predictions by the data from ultimate analysis when inaccessible to the plastic-type data in unknown plastic wastes. Besides, the combination of ultimate analysis input and the DT model also achieved excellent accuracy in liquid and gas composition predictions. © 2023 The AuthorsArticle Citation - WoS: 33Citation - Scopus: 39Bibliometric Analysis of Research Trends on the Thermochemical Conversion of Plastics During 1990-2020(Elsevier, 2021) Khatun, Roomana; Xiang, Huan; Yang, Yang; Wang, Jiawei; Yıldız, GürayThe aim of this bibliometric analysis was to evaluate the trends in literature and the impact of publications that have been published during the period 1990-2020, in the field of thermochemical conversion of plastics, namely gasification, liquefaction and pyrolysis. SCOPUS was used and data was vetted via MS Excel, with analysis being completed via MS Excel and VOSViewer. A total of 1705 publications were used in the study, and China was identified as the most productive country. Pyrolysis was the most researched technology with over 88% of publications, while liquefaction accounted for less than 3% of the total publications. Across all three technologies, polyethylene (PE) was the most commonly occurring type of plastic. Journal of Analytical and Applied Pyrolysis had the highest number of publications and total citations. However, Energy Conversion and Management had a higher impact factor and higher average citations per publication. University of Alicante was identified as the most productive university with a total of 45 publications, while University of Leeds was the most commonly cited with an average of 65 citations per publication. The keyword analysis showed that copyrolysis with biomass and catalytic pyrolysis are gaining increased interests.