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Öğe Developing an adaptive catalyst for an FCC reactor using a CFD RSM, CFD DPM, and CFD DDPM-EM approach(Elsevier Sci Ltd, 2023) Koyunoglu, Cemil; Gunduz, Figen; Karaca, Huseyin; Cinar, Tamer; Soyhan, Galina GulsenCyclone separators, which have an important role in the recovery of catalysts, constituted one of the aims of the study. In the work to be done, the pressure drop occurring during the fcc reaction is also calculated using the Ergun equation and it is aimed to provide the same value in a cyclone separator. In this study, which was presented for the first time in the literature, the best working conditions were determined by simulating the pressure drop in the cyclone separator modeled by using the various catalyst types namely NiMo/ASA-Al2O3, NiMo/p-Al2O3, NiMo/Y-Al2O3, Co-Mo, HZSM-5 zeolite, HY zeolite, pAl2O3, ASA-Al2O3, Y-Al2O3 determined from the literature in the Ergun equation. Among them, NiMo/ASA Al2O3, Co-Mo, HY zeolite, and ASA-Al2O3 were determined as the best catalyst for producing diesel from high oil fractions. Unlike previous studies, the condition that the cyclone separator modeled cleans the catalyst with maximum efficiency also determines the condition that provides low catalyst porosity in the determination of the catalyst type to be determined in diesel production. Due to the accuracy between the calculated and the predicted pressure drop results (about 1,8%), HY zeolite is the best catalyst for cyclone separator geometry. It is widely used to convert high molecular weight hydrocarbon fractions, the high boiling point of petroleum crude oils into olefinic gases, more valuable gasoline, and other products. The purpose of the FCC unit is to increase the refinery conversion and white product yield by converting heavy vacuum gas oil (HVGO) into light hydrocarbons at high temperatures with the aid of fluid catalysis. These two zones (reactor and regenerator) are placed as two different pressure vessels. For these two different systems to work in harmony with each other, unlike in previous studies, the dense discreet phase-Eularian approach was used in the modeling of the catalytic unit and the discreet phase approach was used in the modeling of the cyclone separator. The values required for both processes to work together have been determined approximately.Öğe Direct liquefaction of low rank lignite with peach seed kernel and waste polypropylene for alternative fuel production(Elsevier, 2023) Gunduz, Figen; Olam, Mikail; Karaca, HueseyinIn this study, alternative fuel potentials to petroleum were investigated by direct liquefaction of peach seed kernel (PSK), Mugla-Yatagan lignite (MYL) and waste polypropylene (wPP) separately and together. The effects of PSK and wPP on the yield and selectivity of oil products obtained by direct liquefaction of MYL were also examined. Direct liquefaction experiments were performed in a batch reactor at 1/3 solid/solvent, reaction temperature of 400 degrees C and reaction time of 60 min. The highest total conversion and oil + gas yield were 95% and 85% direct liquefaction of wPP, respectively. According to the calorific value analysis of the chars, the highest gross calorific value of chars was 7709 cal/g in the liquefaction of PSK, and the lowest net calorific value was 2783 cal/g in the liquefaction of MYL. PSK and wPP increased oil yield of MLY from 28% to 60% and 68%, respectively. According to the GC-MS analysis of oils (light liquid products), alternative fuels to gasoline can be produced by direct liquefaction of PSK, wPP and wPP/MYL. Alternative fuels to diesel can be produced by direct liquefaction of MYL and PSK/MYL. The co-liquefaction of MYL with wPP and PSK improved the yield and product components of the oils. The oil + gas yield of MYL was approximately increased PSK by 12% and wPP by 6%.Öğe Obtaining the best temperature parameters for co-carbonization of lignite (yatagan)-biomass (peach seed shell) by structural characterization(Cell Press, 2022) Gunduz, Figen; Akbulut, Yeliz; Koyunoglu, Cemil; Onal, Yunus; Karaca, HuseyinIn this study, Yatagan lignite (YL) and peach kernel shells (PKS) were originally taken separately and in a 1: 1 ratio by weight. Experiments were carried out in a 3-zone heated cylindrical furnace in a steel reactor. Structural characterization of all the solid products obtained was made by FTIR, XRD, and SEM analysis. When the FTIR and XRD spectra of the raw samples are examined, it is seen that they are rich in functional groups. It is seen that the PKS has aliphatic and aromatic structures and cellulosic structure -OH stresses (3500 cm(-1)). The sharp peak around 2918 cm(-1) in Yatagan lignite belongs to the aliphatic C-H stretch. In the XRD spectrum, it is seen that both structures are largely amorphous. The raw PKS contains 3 different amorphous macromolecular structures. Yatagan lignite, on the other hand, contains crystalline peaks of clay and inorganic structures, depending on the ash content, as well as the amorphous structure. As the temperature increases depending on the carbonization temperature, as seen in the FTIR spectrum, the peaks of the functional groups decrease and disappear with the disruption of small macromolecular structures. As a result of the structural adjustment with the temperature increase, M-O-M peaks around 1000 cm(-1) remain due to the aromatic C-H stretching and ash content. The paper centers around test assurance of operating temperatures in the consuming layer during co-carbonization. It is obtained that 800 degrees C is the best temperature condition for the co-carbonization process. It has been concluded that the chars obtained as a result of pyrolysis will be used as a solid fuel in both environmental (the lowest sulfur content) and economic (400 degrees C) sense. However, the fact that it has a very low sulfur content with the increase in the liquid and gas efficiency obtained at high temperatures again proves the production of an environmentally friendly liquid fuel.Öğe Production of activated carbon from duckweed and its effectiveness in crystal violet adsorption(Springer Heidelberg, 2023) Olam, Mikail; Gunduz, Figen; Karaca, HuseyinWith the increase in the use of paint in industrial areas, the rate of dye in wastewater is also increasing. Therefore, the adsorbents used to remove the dye in wastewater are gaining considerable importance. The potential of duckweed (DW) in adsorption of crystal violet (CV), a water-soluble and toxic organic dye, was investigated. Characterization of the adsorbent was made by FTIR, SEM and pHzpc (zero charge point) analyses, and the pHzpc value was 7.75 pH. The effects of temperature, contact time, initial dye concentration, adsorbent dose and solution pH on CV removal were determined. According to the results obtained, the optimum pH, initial dye concentration, adsorbent dose, temperature and contact time were 6 pH, 30 mg L-1, 0.5 g, 30 degrees C and 60 min, respectively. The adsorption data were best fitted with Freundlich isotherm (R-2 = 0.9714) and maximum adsorption capacity of 61.06 mg g(-1) was determined from the Langmuir isotherm. Adsorption of CV by carbonized duckweed (cDW) follows the pseudo-second-order kinetic model (R-2 >= 0.999). Thermodynamic results of the adsorption process show that adsorption can occur spontaneously (Delta G(0) <= -5.302 kJ mol(-1)) and that the process is endothermic (Delta H degrees = 5.92 kJ mol(-1)). The results of this study showed that cDWs are cost-effective adsorbent for effective removal of crystal violet dye.
