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: 1Citation - Scopus: 2Effect of Preparation Method on the Activity of Red Mud Based Catalysts in Hydrogen Production From Biomass(Elsevier Ltd, 2025) Cay, Hakan; Akbas, Nazire Merve; Duman, Gozde; Simsek, Osman; Yildiz, Guray; Wang, Weitao; Yanik, JaleBiomass gasification is a promising technology for hydrogen production. This study presents H2 production from olive tree pruning (OTP), employing a fixed dual-bed reactor that combines OPT gasification and volatile reforming. The thermal steam gasification of OTP was performed at 850 degrees C, followed by the catalytic gasification of volatiles at different temperatures. Red mud (RM) and nickel loaded red mud (Ni-RM) catalysts were used as catalytic bed material. The effects of different operating parameters, i.e. catalytic bed temperature, catalyst preparation method (thermal reduction & plasma reduction), and nickel ratios in catalyst on the yield and composition of produced gases were investigated. The catalyst prepared by reduction under non-thermal plasma showed no effect on the gasification due to the insufficient temperature for the reduction of Fe2O3 and NiO. The results indicated that the bottom bed temperature had a significant effect on the H2 yield, especially in the catalytic experiments. The RM alone shows almost the same activity with Ni-RM on the H2 yield; 1076 mL gas/g OTP and 1128 mL gas/g OTP, respectively. The results of present study showed that reduced RM had as much catalytic activity as Ni loaded reduced RM in hydrogen production.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: 6Citation - Scopus: 7Unveiling the Conditioning Correlation in Ex-Situ Catalytic Pyrolysis of Waste Polyolefins Towards Designated Conversion Into Valuable Products(Elsevier, 2024) Xiang, Huan; Wang, Jiawei; Ma, Peng; Cheng, Yi; Yildiz, GurayThe ex-situ catalytic pyrolysis of waste polyolefin plastics holds promise for producing aromatics and light olefins, with potential integrations in the low-carbon olefin processing industry for producing ethylene, propylene, butadiene, or aromatic hydrocarbons. Employing ZSM-5(50) zeolite, selected for its substantial specific surface area and total pore volume, facilitated the catalytic pyrolysis of household plastic waste through an exsitu pyrolysis-catalysis approach. This study explored the impact of operating parameters, T 1-T 2- C/P mass ratio, namely pyrolysis temperature, catalytic vapor upgrading temperature, and the catalyst/plastic mass ratio, on pyrolysis product yields and distributions. Higher T 2 benefited gas production, accompanied by a notable decrease in C 4 content in gaseous products. A larger C/P mass ratio provided more active sites for pyrolysis reactions, but higher T 2 induced coke formation on the catalyst, leading to ZSM-5(50) deactivation and inhibiting further gas production. Positive effects of T 2 and the C/P mass ratio were observed for the concentration of BTX in the produced oil. The quadratic fitting was engaged in characterising the reaction conditions. Specifically, the 500 -550 -0.25 run achieved the maximum C 2 yield of 30.3 wt%, the 500 -350 -0.4 run obtained the highest yield of C 3 and C 4 of 75.4 wt%, and the run of 575 -450 -0.25 yielded the highest amount of BTX of 17.2 wt%. These findings provide valuable insights into the designated conditioning of catalytic pyrolysis for plastic waste valorisation.Article Citation - WoS: 3Citation - Scopus: 3Continuous Flow Pyrolysis of Virgin and Waste Polyolefins: a Comparative Study, Process Optimization and Product Characterization(Springer, 2024) Ekici, Ecrin; Yildiz, Guray; Yildiz, Magdalena Joka; Kalinowska, Monika; Seker, Erol; Wang, JiaweiUnder optimal process conditions, pyrolysis of polyolefins can yield ca. 90 wt % of liquid product, i.e., combination of light oil fraction and heavier wax. In this work, the experimental findings reported in a selected group of publications concerning the non-catalytic pyrolysis of polyolefins were collected, reviewed, and compared with the ones obtained in a continuously operated bench-scale pyrolysis reactor. Optimized process parameters were used for the pyrolysis of waste and virgin counterparts of high-density polyethylene, low-density polyethylene, polypropylene and a defined mixture of those (i.e., 25:25:50 wt %, respectively). To mitigate temperature drops and enhance heat transfer, an increased feed intake is employed to create a hot melt plastic pool. With 1.5 g<middle dot>min-1 feed intake, 1.1 L<middle dot>min-1 nitrogen flow rate, and a moderate pyrolysis temperature of 450 degrees C, the formation of light hydrocarbons was favored, while wax formation was limited for polypropylene-rich mixtures. Pyrolysis of virgin plastics yielded more liquid (maximum 73.3 wt %) than that of waste plastics (maximum 66 wt %). Blending polyethylenes with polypropylene favored the production of liquids and increased the formation of gasoline-range hydrocarbons. Gas products were mainly composed of C3 hydrocarbons, and no hydrogen production was detected due to moderate pyrolysis temperature.