Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Esterification of Free Fatty Acid Obtained From Waste Cooking Oil Over Solid Catalyst(Izmir Institute of Technology, 2022) Şeker, Erol; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe objective of this study was to investigate effect of reaction temperature, catalyst weight percentage and composition of Al2O3/SiO2 on conversion of FFA obtained from waste cooking oil (WCO) to take place esterification reaction by using Box-Behnken design. Statistical analysis demonstrates that catalyst weight percentage and temperature were insignificant statistically. Alumina composition was found as significant parameter at certain conditions by considering statistical analysis. It was seen that conversion of Free Fatty Acid (FFA) increases as composition of Al2O3 in Alumina/Silica catalyst increases. %80 Al2O3/20% SiO2 catalyst was found as promising catalyst since conversion of FFA with the catalyst was 32% at 80°C and 15:1 alcohol to FFA ratio. Besides, it was found that alcohol to FFA ratio affected the conversion reversely. When alcohol to FFA ratio was reduced to 2:1, conversion of FFA increased to 41%. The prepared catalysts were characterized by XRD and TPD analysis. Activity of catalysts were attributed to acidic strength and Bronsted acid sites on the aluminum sulfate in the catalysts. After screening effects of catalysts and reaction conditions, optimum levels of parameters were used to investigate the esterification reaction of model WCO. This reveals that conversion of FFA was found as 11% at 80°C and 15:1 alcohol to FFA ratio. Finally, the proposed catalyst does not have catalytic activity of hydrolysis reaction of oil at applied conditions.Master Thesis Anaerobic Digester Modelling for Production of Biogas From Waste Hazelnut Husk(Izmir Institute of Technology, 2022) Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyAnaerobic digestion is a degradation process of complex organic matters into methane and carbon dioxide in an oxygen-free environment maintained by microorganisms. An advantage, besides energy production, is it is a waste management technique. Hazelnut husk is a valuable raw material for the anaerobic digestion process with more than 55 % cellulose and hemicellulose content. Anaerobic Digestion Model No. 1 (ADM1) developed by IWA Group was used in this study. This master thesis modeled biogas production by co-digestion of cattle manure and hazelnut husk process in MATLAB. The goal was to evaluate the methane amount of a household bioreactor. Tanks-in-series model with 3 CSTRs was chosen after residence time distribution (RTD) analysis. Ten different cases were investigated to show the effects of carbon source/manure ratio, temperature, carbon source type, total solid (TS) amount, reactor type, and RTD analysis. The carbon source/manure ratio improves the methane yield as it increases. When the ratio is 1, methane yield is 0.229 L/kgVS whilst yield is 0.224 L/kgVS if the ratio is 0.1. The temperature effect on the process is significant. In the thermophilic case, the methane production is 0.432 L/d which is the highest amount compared to mesophilic and psychrophilic cases. When food waste is used as a carbon source with a ratio of food waste/manure of 0.1, the methane production is 0.410 L/d while it is 0.403 L/d in hazelnut husk digester. When the TS amount is doubled, the methane yield goes down from 0.224 to 0.149 L/kgVS because the residence time is not long enough to digest it as well as in case with lower total organic carbon level. In unmixed, mixed, and Chinese Dome Digester types of reactors, methane productions are 0.403, 0.646, and 0.552 L/d, respectively. In the ideal case, the methane production is 1.525 L/d which indicates the necessity of RTD analysis.Master Thesis Carbon Dioxide Hydrogenation on Alumina Supported Ruthenium Catalysts(Izmir Institute of Technology, 2019) Hamza, Gökmen Oğuzcan; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study the effect of basicity of catalyst is investigated using different metal oxide supported Nickel and Ruthenium catalyst. The basic strength of catalysts was orchestrated with using different types of metals and different composition of supports. In this study Al2O3-CaO, Al2O3-MgO, Al2O3-BaO supports were used with nickel and ruthenium catalyst, which synthesized with sol-gel method. Different mass ratios of supports were used such as; 100%, 70%/30%, %50/50%, 20%/80% respectively. For all metal oxides Nickel loadings are 1 %, 5% and Ruthenium loading is 0.5%. Calcination temperature was 500 0C with 6 hours. All catalysts were used in methanation reaction with conditions varies between 300-600 0C, inlet ratio of CO2/H2 1/4 to 1/6 and GSHV 5000h-1/10000h-1. The products were analyzed using GC and catalysts were analyzed using XRD NH3-TPD and BET. Nickel load selected as 1%, magnesium supported catalysts' the main crystallites were aluminum oxide and magnesium oxide for 30%,50%,80; respectively. Calcium supported catalyst had had alumina and calcium oxide crystallites for 30%,50% respectively. Barium supported catalysts had had alumina and barium mix oxide crystallites for 30%,50% respectively. For 5% Nickel loaded 70-30% alumina magnesia mix oxide catalyst magnesia and alumina crystallites are found. Aluminum magnesium mix oxide catalysts had higher basicity than aluminum barium mix oxide catalysts for 1% nickel catalysts. Ruthenium based magnesium alumina mix oxide catalyst had higher basicity than nickel-based magnesium alumina catalysts. Ruthenium catalysts had higher total performance towards both of the reverse water gas shift reaction and carbon dioxide methanation than nickel-based catalysts.Master Thesis Investigation of Different Uv Stabilizer Effects on Hdpe Grades(Izmir Institute of Technology, 2019) Germen, Oktay; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, a performance Hindered Amin Light Stabilizer (HALS), used to prevent the structure of polymeric materials from UV and thermal degradation, was investigated using High Density Polyethylene (HDPE) injection grade. The primary goal of this study is to understand the effects of different HALS types, that consist of low molecular mass and high molecular mass, on mechanical and physical properties of HDPE using a design of experiment method. In addition, Minitab program was used to analyze the data, obtained with the experimental design, with ANOVA analyses to estimate the OIT and Loss Elongation% responses of the samples made with varying HALS amounts and types. Briefly, Elongation Lost% which is the ratio of Elongation% Before Aging to Elongation % After Aging and OIT(Oxidative Induction Time) were studied in different recipes of HDPE Injection Molding Plaque specimens in order to measure the effect of HALS1 (Tin770), HALS2(Tin622) and HALS3(Chim944) on aging. One-year of aging was simulated using a standard aging chamber. It was observed that synergetic effect of HALS1 with HALS3 was much more effective than thatof HALS2 with HALS3. Moreover, it was determined that the samples containing antioxidant which did not contain any HALS additive were completely degraded at the end of the same aging process. This study showed that OIT results of samples were affected directly by the amount of HALS3 which protected the polymer against long-term exposure to UV radiation and high temperature whereas neither HALS1 nor HALS2 showed the same protection.Master Thesis Development of Kinetic Model for Industrial Ethylene Oxide Catalyst by Using Model-Targeted Experimentation Approach(Izmir Institute of Technology, 2019) Sarrafi, Şahin; Şeker, Erol; Şeker, Erol; Arkun, Ziya Yaman; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyEthylene oxide (EO) is produced via selective oxidation of ethylene with oxygen using a Ag supported on -Al2O3 catalyst. The ethylene epoxidation reaction is desired, whereas the ethylene and EO combustion reactions are not. Proposed study is aimed at developing a tailor-made kinetic model in order for making use in the industrial ethylene oxide reactors which are of paramount importance from the viewpoint of process economics and the greenhouse gas (GHG) induced various environmental exposures. With aging of the catalyst, the trade-off between selectivity and productivity becomes gradually more prominent. Along with the compensation of loss of active sites under the favor of increasing of the temperature, catalyst still provides sustainable commercial yields at the expense of excess feedstock consumption which in turns leads to boost GHG emissions by releasing more carbon dioxide (CO2) into the atmosphere. To maintain catalyst activity for a longest period possible, controlling process variables more preciously with a robust model is very demanding issue throughout the last two decades. Within the scope of this thesis, model-targeted experimentation approach was used assisting by gPROMS software in determining intrinsic kinetics of the commercial catalyst in use through integral reactor coupled with gas chromatography. During the course of the kinetic experiments, the effect of VCM used as a promoter together with inhibiting effects of product gases such as CO2 and EO were also investigated and included into the kinetic model to be derived.Master Thesis Biofuels Production Using Canola Oil Over Heterogeneous Catalysts(Izmir Institute of Technology, 2017) Özdoğru, Bertan; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe goal of this study was to investigate the activity of Ni loaded on Al2O3-SiO2 supports prepared with different acids for the production of biofuel grade compounds while using canola oil as our feedstock. While keeping the reaction conditions constant, catalyst preparation parameters such as aluminum concentration, nickel concentration, calcination temperature, and acid types investigated with statistical methods by constructing Box Behnken design using three continuous parameters with two levels and one categorical parameter with three level. Responses considered in this study were aldehyde, ester, organic acid and other compound yields calculated from the GC-MS analysis. After ANOVA analysis, empirical models calculated from this analysis used to optimize the catalyst preparation parameters. Three catalysts, one for each acid type, selected to investigate the validity of our model. Analysis did on these catalysts have shown that both 0% Ni/25% Al2O3-75% SiO2 w/H2SO4 at 900oC and 20% Ni/75% Al2O3-25% SiO2 w/H3PO4 at 900oC catalysts gave good ester yields with good organic acid utilization. 20% Ni/75% Al2O3-25% SiO2 w/H3PO4 at 900oC catalyst was exceptional in ester selectivity aspect while 0% Ni/25% Al2O3-75% SiO2 w/H2SO4 at 900oC catalyst was in organic acid utilization aspect. Presence of aluminum phosphate crystal phase observed with XRD resulted in 20% Ni/75% Al2O3-25% SiO2 w/H3PO4 at 900oC catalyst having the highest selectivity towards ester production. Combination of weak and strong acid sites increased the organic acid selectivity while lowering the selectivity towards esters for 0% Ni/25% Al2O3-75% SiO2 w/H2SO4 at 900oC catalyst. From the low organic acid utilization observed with 10% Ni/25% Al2O3-75% SiO2 w/HNO3 at 500oC and, 10% Ni/50% Al2O3-50% SiO2 w/H2SO4 at 700oC catalysts which had high amounts of weak acid sites, it could be said that organic acids can only be reacted over strong acid sites.Master Thesis Biofuels Production Using Starch Over Heterogeneous Catalysts(Izmir Institute of Technology, 2017) Uçaroğlu, Merve; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, the effect of acidity and acidic strength on the product distribution in the hydrolysis of starch was investigated on mixed oxide supported Ni catalysts prepared using different types of metal oxides with varying compositions and, the calcination temperatures. SiO2/Al2O3 (mass ratios of 30/70, 50/50, 70/30) and ZnO/TiO2 (mass ratios of 10/90, 30/70, 50/50) catalysts were synthesized using a sol-gel method. For all the ratios and metal oxide types, Ni weight loading was 1%, 5.5% and 10%. The calcination temperatures used for all the SiO2/Al2O3 catalysts were 500 oC, 700 oC and 900 oC. The calcination temperatures used for all the ZnO/TiO2 catalysts were 300 oC, 400 oC and 500 oC. The starch hydrolysis reaction was carried out at 90 oC for the reaction time of 24 h. The concentration of the products was determined using HPLC and acidity/acidic strength of the catalyst were measured using NH3-TPD. This study showed that the product distribution was affected by catalyst compositions and calcination temperatures that resulted varying total acidity and acidic strength. Unidentifiable saccharides, maltotriose, xylose, and glucose were produced during the hydrolysis of starch on all the SiO2/Al2O3 supported Ni catalysts while there were only unidentifiable saccharides on all the ZnO/TiO2 supported Ni catalysts. The products distribution was found to strongly dependent on the nature of the acid type; for instance, Al2(SO4)3 crystalline phase was more active than the acid type on ZnO and TiO2 anatase crystalline phases. In addition, the glucose yield increased on the large Al2(SO4)3 crystallite sizes, e.g. the catalyst having 42 nm of Al2(SO4)3 crystallite size gave ~15% glucose yield whereas that having 10.5 nm of Al2(SO4)3 crystallite size gave 0%. Besides, acidic strength was more important than total acidity for the same acid type. In fact, the lower the acidic strength, such as located at 150 oC, higher the glucose yield was obtained.Master Thesis Catalytic Surface Coatings for Household Ovens(Izmir Institute of Technology, 2016) İzer, Alaz; Şeker, Erol; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe emission of harmful volatile compounds, such as aldehydes, and also carbon monoxide could occur during cooking processes at home or industry due to the combustion and cracking of spilled vegetable oil on the walls of an oven. It is known that the by-products generated during cooking could affect human health and environment if they are properly vented or removed. To eliminate the health and environmental problems related to oven emission, self-cleaning catalytic materials coated walls for ovens seem to be viable alternative to the toxic and time consuming chemical cleaning solutions. In this project, a sol-gel method and also the dip coating technique was used to produce a catalytic material coated aluminum plates. Specifically, the calcination time and the temperature were studied to better understand the relationship between the textural/chemical properties of the catalyst coated metal plates and their catalytic activities. The studied calcination temperatures were 450°C, 500°C and 550°C whereas the calcination time were 10 min, 30 min and 60 min for each type of catalyst. Aluminum oxide supported nickel and also aluminum oxide - manganese oxide supported nickel catalysts were prepared as the catalyst that were used in coating. The catalytic activities of the catalyst coated plates were determined using canola oil as a function of reaction time which were 1h at 170°C and 200°C. The results have been shown that the most convenient calcination conditions for the canola oil combustion were 500°C for 30 minutes by using aluminum oxide – manganese oxide supported nickel catalyst.Master Thesis Catalytic Methanol Combustion(Izmir Institute of Technology, 2015) Demirkaya, Emre; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThroughout this study, the major goal is to analyze the product distribution of methanol combustion at different reaction conditions, such as, varying space velocities, different initial temperatures, on 2% Pt/Al2O3 catalyst. The catalyst support material, alumina, was prepared by using a single-step sol-gel method and platinum was added by using the impregnation method. The reaction was conducted in a tubular reactor. In this work, the maximum steady state temperature at room temperature experiment was achieved almost same within the error for 2.4 s-1 and 2.8 s-1 space velocity for fresh catalyst, and also, the conversion to CO2 during the methanol combustion reaction for all the space velocities (2.4 s-1, 2.8 s-1 and 3.1 s-1) were found to be ~100%. Another parameter that was studied was the temperatures below the room temperature. The reaction was performed at -13oC, 0oC, 7oC and 15oC temperatures. With decreasing initial temperature, the steady state temperature was also found to be decrease. This was correlated with the product distribution and with decreasing initial temperature, CO2 conversion decrement was observed.. Methyl formate was detected to be the main byproduct that was produced under all the space velocities at temperatures lower than room temperatures. The catalyst was active even at -13oC. Therefore, it showed that it could be used as a catalyst for an external heater to provide necessary heat to reach the direct methanol fuel cells operating temperature at and below room temperature. Other than the other catalysts that was investigated in literature, our catalyst does not need to heat up the reactor. Once the fuel is supplied, the system reaches the necessary operating temperature by itself. This is desirable especially in portable DMFCs. The catalytic methanol combustion system investigated in this study seems to be promising to easily replace the lithium-ion batteries for portable electronic systems, especially ones used in the military.Master Thesis Catalytic Oxidation of Volatile Compounds Generated During Frying Process Using Sunflower Oil(Izmir Institute of Technology, 2014) Aytaç, Arda; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe main goal of this study is to investigate the effect of metal type, metal oxide type and metal/oxide loading on the conversion as a function of temperature for the combustion of sunflower oil over modified single step sol-gel made Al2O3 supported metal and mixed metal oxides. All catalysts were tested at 170 oC and catalysts giving good activity among them were tested also at 195 oC. As a monometallic catalysts, Ni/Al2O3 (10, 25, 50 % Ni loaded), Ni/Al2O3 (50 % Ni loaded) derived from different Ni precursors, Mn/Al2O3 (50, 70 % Mn loaded) and as a bimetallic catalysts, Ni- Mn2O3/Al2O3 with Ni/Mn mass ratios of 20:56 and 23:66 catalysts were synthesized by a modified single step sol-gel method. In addition, in synthesizing step of bimetallic catalysts, the order of adding precursor was studied. The catalytic activities of all the catalysts were compared to 3% Pt/alumina. The combustion performances of pure Al2O3 and catalyst coated aluminum plates were also considered and volatile compound analysis was monitored by GC-MS and the amounts of CO and CO2 generated during the combustion were calculated quantitatively from GC analyses. The characterization of the samples was performed by XRD and BET techniques and it was observed that among the monometallic oxide catalysts, 50% MnxOy/Al2O3 showed slightly better activity at 170 oC due to the its highly reducible oxide property. Among mixed metal/metal oxide catalysts, 20% Ni/56% Mn2O3/Al2O3 (First Ni precursor added) was the catalyst demonstrated the highest catalytic activity at both temperatures. It seems to be due to the interaction between nickel and manganese oxide. In addition, the combustion was also carried out by using catalyst coated aluminum plates to observe if the best catalyst formulation found from the studies on the powder catalysts would be applicable for the self-cleaning metal plates used in the household ovens. In fact, the catalyst coated plates showed higher conversion at 170 oC in 1 h than that observed on the powder catalyst due to the elimination of internal mass transfer limitation.