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Öğe Hydrothermal synthesis of magnetic nanocomposite from biowaste matrix by a green and one-step route: Characterization and pollutant removal ability(Elsevier, 2019-04) Sayğılı, HasanThis study aimed to produce an industrial waste-based novel magnetic nanocomposite (Fe@GPHC) by a facile and one-step hydrothermal carbonization (HTC) method. In order to characterize of Fe@GPHC, X-ray fluorescence spectroscopy (XRF), Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), Vibrating-sample magnetometer (VSM), and elemental (ultimate) analyses were applied. Characterization results showed that during the HTC process, the Fe nanoparticles (FeNPs) were successfully incorporated on biowaste matrix. In addition, the Fe@GPHC was used to test its adsorptive property. For this, methylene blue (MB) and methyl orange (MO) were selected as a simulated pollutant. A batch method was used to perform the adsorption experiments. The maximum adsorption capacity of Fe@GPHC was 11 mg g(-1) and 8.9 mg g(-1) for MB and MO, respectively. This study provides a feasible and simple approach to design and synthesis of high-performance functional magnetic material in a cost-effective way.Öğe Prediction of transport properties for the Eastern Mediterranean Sea shallow sediments by pore network modelling(Elsevier, 2019-05) Merey, ŞükrüThe Eastern Mediterranean Sea has gas hydrate potential as well as its conventional natural gas potential.Numerical simulations are crucial to predict gas and water production from gas hydrate reservoirs because theyare needful to determine gas production strategies. However, the transport properties of the EasternMediterranean Sea shallow sediments are missing in literature. In this study, the transport properties (porosity,absolute permeability, relative permeability, and capillary pressure) of the Eastern Mediterranean Sea shallowsands were estimated by pore network simulations with OpenPNM. In order to generate pore networks in theconditions of the Eastern Mediterranean Sea, the core data of Ocean Drilling Program Leg 160 was evaluated inthis study. In pore network simulations, it was observed that porosity and absolute permeability increase as porediameter and throat diameter increase. On the other hand, capillary pressure decreases. Thefitting parameters toOpenPNM modelling data for the relative permeability equation of Stone were calculated as: 0.02–0.14 for Srw,1.8–3.57 for ngand 1.9–6.0 for nw. Thefitting parameters to OpenPNM modelling data for the capillary pressureequation of Van Genuchten were calculated as: 0.866–0.945 for m and 1.375 × 104-5.90 × 105Pa for P0. Theseparameters were suggested for numerical gas hydrate production simulations in the Eastern Mediterranean Sea.Numerical simulations at different cases were held by HydrateResSim for gas hydrates to investigate the effect oftransport properties on gas and water production in the conditions of the Eastern Mediterranean Sea. It wasobserved that gas production, water production and production time were significantly affected by transportproperties.Öğe Analysis of the effect of experimental adsorption uncertainty on CH 4 production and CO 2 sequestration in Dadas shale gas reservoir by numerical simulations(Elsevier, 2019) Merey, ŞükrüThe importance of unconventional gas reservoirs such as shale gas reservoirs has increased with the decline of conventional gas reservoirs and advancement in horizontal drilling and hydraulic fracturing in the world. Recently, there have been many exploration activities in Dadas shales, Turkey. Previously, the adsorption capacities of CH 4 and CO 2 on Dadas shale samples were measured by using volumetric adsorption experimental set-up. Although adsorption uncertainties of these experiments were calculated, their effects on CH 4 production or CO 2 sequestration in Dadas shales were not evaluated in field scale. In this study, the numerical simulations for CH 4 gas production via 500 m long horizontal well from Dadas shale gas reservoir with different adsorption cases due to experimental adsorption uncertainties were conducted by using TOUGH + RealGasBrine. It was observed that initial CH 4 adsorption capacity of Dadas shales varies from 2.1% to 20.9% because of experimental adsorption uncertainty and absorbed gas volume corrections. Numerical simulations showed initial adsorbed gas % and final adsorbed gas % vary significantly. Similarly, the injection of CO 2 into the depleted Dadas shale gas reservoir was analyzed by numerical simulations at different adsorption cases due to experimental adsorption uncertainty and adsorbed gas volume correction. Final adsorbed CO 2 % varies from 18.1% to 27.5%. Furthermore, there are important differences in the amount of CO 2 injected, final adsorbed CH 4 % and final adsorbed CO 2 % during CO 2 injection simulations. The main reasons of these differences are experimental adsorption uncertainty and adsorbed gas volume correction. This study showed that the volumetric adsorption experimental method is not reliable in low adsorption values as in Dadas shales. It only gives adsorption ranges. The implication of this study is that the effect of experimental adsorption uncertainty obtained with the volumetric adsorption method on CH 4 production or CO 2 sequestration in Dadas shale gas reservoir is significant in field scale.Öğe Optimized preparation for bimodal porous carbon from lentil processing waste by microwave-assisted K 2 CO 3 activation: Spectroscopic characterization and dye decolorization activity(Elsevier, 2019) Sayğılı, Hasan; Akkaya Sayğılı, GülbaharThis paper describes lab-scale experiments for producing optimal activated carbon (LWAC)with bimodal porous (mixed micro-mesoporous)texture under optimized conditions from lentil processing waste (LW)by microwave-assisted K 2 CO 3 activation. The influences of various operating parameters were evaluated including impregnation ratio (IR), carbonization temperature (CT)and carbonization time (Ct). The BET surface area (S BET )and total pore volume (V T )were chosen as main criteria in optimization. The optimized parameters were IR ratio of 3:1, CT of 800 °C and Ct of 1 h. The physicochemical properties of LW and LWAC were identified with diverse analytical techniques. LWAC possessed high S BET of 1875 m 2 /g and large V T of 0.995 cm 3 /g. The LWAC was then tested for its feasibility as cationic (Methylene blue (MB))and anionic (Methyl orange (MO))dyes adsorbent. It was found that LWAC has an adsorption capacity of 625 mg/g for MB and 476 mg/g for MO at 30 °CÖğe Evaluation of drilling parameters in gas hydrate exploration wells(Elsevier, 2018-08-31) Merey, ŞükrüGas hydrates are crystalline ice-like structures formed from water and gas molecules at high pressure and low temperature conditions. They are considered as near-future energy resources. Recently, there have been many drilling activities in gas hydrates in both permafrost regions (mainly Mallik wells, Canada; Ignik Sikumi #1 well, Alaska; Mount Elbert #1, Alaska) and marine sediments (the wells drilled in Gulf of Mexico and India drilling expeditions). In this study, it is aimed to evaluate and analyze logging-while drilling data (LWD) and other drilling data of these drilling activities. Initially, all drilling parameters (i.e. rate of penetration, weight on bit, torques, mud logs, etc.) of these wells were collected and drawn to see the change in parameters with depths. In order to indicate the changes in drilling parameters in the sediments containing gas hydrates, gas hydrate saturations were estimated from resistivity logs and NMR logs in this study. High resistivity log values and methane peaks in drilling fluid were good indicators of gas hydrate existence. During the drilling of permafrost formations and gas hydrates deposited in coarse sands as pore filling, the rate of penetration generally decreased. Differently, there was not almost any change in the rate of penetration during the drilling of fracture-filling gas hydrates within silts/clay in India. Borehole enlargements (washouts) were commonly seen in the wells drilled in marine sediments (Gulf of Mexico and Indian expeditions). However, this effect was minimum during the drilling of the wells in permafrost regions. This difference is due to the loose sediments in marine environment. Furthermore, gamma and density logs were seriously affected by washouts, mainly in marine sediments. It was observed that pore-filling gas hydrates affect the rate of penetration and keep the sediments stable because well collapses mainly occurred in the sediments without any gas hydrates. However, the temperature of drilling fluid should be close to the temperature of gas hydrate zones to reduce the effect of drilling on gas hydrate dissociation for the wells both in permafrost and marine sediments. In Gulf Mexico and Indian drilling expeditions, riser and wellhead equipment were not used. However, the usage of surface casing might decrease the risk of borehole collapses due to very loose sediments close to sea floor. Another important outcome of this study is that the pressure gradient follows hydrostatic pressure gradients according to the pressure analysis within gas hydrate stability zones of marine sediments. Finally, the analyses of drilling parameters revealed that drilling through gas hydrate bearing strata is not as risky as it might have been considered. The key is hidden in appropriate drilling design.
