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    Hydrogenation reactions of kerosene on nickel-based catalysts
    (Elsevier Ltd, 2023) Kömürcü, Hasan; Yılmaz, Kadir; Gürdal, Savaş; Yaşar, Muzaffer
    The hydrotreating of kerosene was studied to develop a crude kerosene distillate to produce products with specifications suitable for marketing as kerosene and rocket grade fuel. To saturate the aromatic structures from kerosene, hydrogenation experiments were carried out in a batch steel reactor with different amounts (20 ml and 40 ml) of crude kerosene, using silica-supported nickel and kieselguhr supported nickel-sulfur catalysts. The catalysts were analyzed with Brunauer, Emmett ve Teller (BET), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), and x-ray diffraction analysis (XRD). The aromatic fractions and paraffin structures content of the obtained samples were examined. The experiments were carried out at 200–220 °C temperature with 5 bar hydrogen initial pressure for 2 h. The obtained products were analyzed by performing a 1H NMR analysis. According to proton NMR result, the ratio of paraffinic methylene, beta methyl, epsilon methylene groups of 20 ml crude kerosene with kieselguhr supported nickel-sulfur is more than 4.5 times compared to crude kerosene, and % the percentage of aromatic hydrogen structures of it is two times lower. As a result of hydrogenation experiments with both nickel-based catalysts, aromatic hydrogen structures in crude kerosene were reduced. The total H/C ratio of rocket grade hydrocarbon fuels increased after hydrogenation experiments. For this reason, the scope of ongoing research can be extended to hybrid rocket propellants (SP-1) used in hybrid rocket engines.
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    The Effect of Ionic Liquids Incorporation on the Self-healing Behavior of the Bitumen
    (Institute for Ionics, 2024) Arca, Serhat; Gürdal, Savaş; Canıaz, Ramazan Oğuz; Yılmaz, Kadir; Kömürcü, Hasan; Yılmaz, Kadir
    In the asphalt pavements, which are prepared by mixing bitumen and aggregates, fatigue cracking and thermal cracking failure occur due to continuous loading and climate conditions. Extending the life of asphalt pavements is very important from an environmental and economic point of view. In this study, reactions are conducted to investigate the effects of six ionic liquids (IL) with different side-chain lengths on the self-healing properties of bitumen. Thermogravimetric analysis and differential scanning calorimetry analysis are performed for ionic liquid characterization, while for bitumen characterization, Saturates, Aromatics, Resins, Asphaltenes (SARA) fractionation of bitumen and Gel Permeation Chromatography, Nuclear Magnetic Resonance, Elemental Analysis of these sub-fractions were performed. In addition, two new test methods have been developed to measure the self-healing capacity of bitumen. The first method shows the effects of rest times when intermittent loading is applied to the sample at high temperatures, while the other method was developed to demonstrate the self-healing ability of bitumen at low temperatures with long rest periods. Stripping tests, asphalt fatigue tests and zeta potential measurements are done to investigate the effects of ionic liquids on bitumen and aggregate interactions. The results indicated that different ionic liquids have different effects on asphalt self-healing mechanism. IL improved the self-healing performance of asphalt 40% at high temperatures, and 100% at low temperature while stripping properties 25% and asphalt fatigue life 20% improved. Therefore, it can be concluded that different bitumen-IL modification recipes could be used for self-healing of asphalt pavements, depending on climatic conditions and traffic density.
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    Öğe
    Uncovering the Hydrocracking Efficiency of Iron-Based Catalysts: A Novel Approach to Asphaltene Transformation in Iranian Heavy Oil
    (2024) Yılmaz, Kadir; Gürdal, Savaş; Yaşar, Muzaffer
    In the quest for optimal asphaltene conversion, this study investigated a range of cost-effective and easily accessible catalyst precursors, targeting both high yields of lighter products and minimal coke formation. The hydrocracking experiments were conducted within a 10 ml bomb-type reactor equipped with a reciprocating stirrer operating at a reciprocation rate of 200 times per minute. The experiments were performed at a temperature of 425°C for a duration of 90 minutes, with an initial hydrogen pressure of 100 bar. The outcomes of each experiment were assessed in terms of liquid products, coke production and C5- gas products. To analyze the Iranian heavy asphaltene, Nuclear Magnetic Resonance (1H NMR), Gel Permeation Chromatography (GPC) and elemental analysis were employed. Gas products were characterized using Gas Chromatography (GC). The investigation aimed to identify the catalyst precursor mixture that would maximize asphaltene conversion while minimizing coke production. A series of catalyst precursors, encompassing FeSO4·H2O, its binary mixtures with metal oxides (Fe2O3, Al2O3, CaO, SiO2), and combinations of Fe2O3, Al2O3, and SiO2 with elemental sulfur, were evaluated. The experimental results demonstrated that the toluene-soluble fraction (TSF), which includes the middle distillate portion, could be increased to a maximum of 56% while concurrently reducing the coke yield to 19%, down from the initial 36.9% when no precursor was used.