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Öğe Chemical Desulfurization of Low-Rank Muğla-Yatağan and Kütahya-Tunçbilek Lignites(International Pittsburgh Coal Conference, 2023) Gündüz F.; Karaca H.Impurities present in coal structures, when combusted, release harmful emissions into the environment. Sulfur is a primary impurity in this context. One of the most effective methods for removing inorganic materials from lignite, a type of coal, is chemical desulfurization. In this study, lignite samples from two different reserves in Turkey were treated with H2O2 and H2SO4 reagents at varying temperatures, reagent concentrations, and durations to examine sulfur removal. According to the results obtained, the sulfur removal rates for Tunçbilek and Yatağan lignites were found to be 31.81% and 48.12% respectively at 30% H2O2 concentration, and 32.12% and 57.14% respectively at 30% H2O2 and 0.1 N H2SO4 concentrations. As the concentration of the chemical reagent increased, sulfur removal also increased. In a 20% H2O2 solution under process conditions of 30-90 minutes, pyritic sulfur in Tunçbilek lignite decreased from 0.73% to 0.21%, and in Yatağan lignite, it decreased from 0.43% to 0.20%. In the desulfurization process conducted at 50°C with H2O2 reagent, the sulfatic sulfur content in Tunçbilek and Yatağan lignites was obtained as 0.21% and 0.07% respectively. The method used in this study proved effective in removing sulfur from low-rank lignites. It is considered an effective method to reduce the harmful effects of sulfur on the environment. © 2023 40th Annual International Pittsburgh Coal Conference, PCC 2023. All rights reserved.Öğe Synthesis of an innovative SF/NZVI catalyst and investigation of its effectiveness on bio-oil production in liquefaction process alongside other parameters(Springer, 2024) Ersöz K.; Bayrak B.; Gündüz F.; Karaca H.Today, new energy sources alternative to fossil fuels are needed to meet the increasing energy demand. It is becoming increasingly important to constitute new energy sources from waste biomass through the liquefaction process. In this study, walnut shells (WS) were liquefied catalytically and non-catalytically under different parameters using the liquefaction method. In this process, the effect of silica fume/nano zero-valent iron (SF/NZVI) catalysts on the conversion rates was investigated. The catalyst was synthesized by reducing NZVI using a liquid phase chemical reduction method on SF. The SF/NZVI catalyst was characterized by scanning electron microscopy- energy dispersive X-ray (SEM–EDX), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis. The effect of various process parameters on the liquefaction process was investigated. In this context, the reaction temperature ranged from 300 to 400 °C, the solid/solvent ratio ranged from 1/1 to 1/3, the reaction time ranged from 30 to 90 min, and the catalyst concentration ranged from 1 to 6%. According to the results obtained, the most suitable operating conditions for non-catalytic experiments in liquefaction of WS were found to be temperature of 400 °C, reaction time of 60 min, and solid/solvent of 1/3. In catalytic conditions, the optimum values were obtained as temperature of 375 °C, reaction time of 60 min, solid/solvent ratio of 1/3, and catalyst concentration of 6%. The highest total conversion and (oil + gas) % conversion were 90.4% and 46.7% under non-catalytic conditions and 90.7% and 62.3% under catalytic conditions, respectively. Gas chromatography/mass spectrometry (GC/MS) analysis revealed the bio-oil was mainly composed of aromatic compounds (benzene, butyl-, indane and their derivatives,) and polyaromatic compounds (naphthalene, decahydro-, cis-, naphthalene, 1-methyl-.). The aim of increasing the quantity and quality of the light liquid product in the study has been achieved. © The Author(s) 2024.
