Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Access type: Open accessSubject: search.filters.subject.Biodiesel

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  • Master Thesis
    Experimental Spray Investigation of Methyl Ester and Ethyl Ester Type Biodiesel Fuels in a Constant Volume Combustion Chamber
    (Izmir Institute of Technology, 2020) Ulu, Anılcan; Özkol, Ünver; Yıldız, Güray; Özkol, Ünver; Yıldız, Güray; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Biodiesel fuels are promising fuels that can reduce pollutant emissions from diesel engines. Therefore, they are still being investigated in every aspect. In this study, it was aimed at comparing the spray characteristics of methyl ester and ethyl ester type biodiesel fuels with those of fossil diesel fuel. Besides, this study aimed to investigate the spray characteristics of ethyl esters on which few studies have been done, and to help eliminate this gap in the literature. For these purposes, 4 different methyl esters from corn, sunflower, canola and cotton oils, and 2 different ethyl esters from corn and sunflower oils were produced. Commercial diesel fuel was used to compare the characteristics of these fuels. Firstly, physical properties of the fuels produced were investigated to better understand the spray investigation, and it was observed that biodiesel fuels had bigger density and viscosity values than fossil diesel fuel. Additionally, it was found that methyl esters had larger density and smaller viscosity values than ethyl esters. After that, spray characteristics of all fuels were investigated in a constant volume combustion chamber under ambient pressures of 0, 5 and 10 bar, and injection pressures of 600 and 800 bar. Then, these fuels were cnompared to each other. After the experiments, biodiesel fuels were found to have longer spray penetration lengths and narrower spray angles than diesel fuel, although there were no significant differences between them. This may be due to higher density and viscosity values of biodiesel fuels. Furthermore, no significant distinctions were found between the spray characteristics of ethyl esters and methyl esters. In addition, it was observed that ambient and injection pressures were important parameters affecting the spray pattern. As a result, it was obtained that biodiesel-air mixing was slightly worse than diesel-air mixing. However, their potential to reduce pollutant emissions may cause this difference to be ignored. Moreover, it was found that ethyl esters had similar spray characteristics as methyl esters. Hence, ethyl esters are promising to replace methyl esters.
  • 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 Technology
    The 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
    Cloning, Heterologous Expression and Purification of Various Wax Ester Synthases in Escherichia Coli
    (Izmir Institute of Technology, 2017) Ovacık, Kamil; Arslanoğlu, Alper; Arslanoğlu, Alper; 04.03. Department of Molecular Biology and Genetics; 04. Faculty of Science; 01. Izmir Institute of Technology
    Biodiesel, known all around theWorld, is a diesel fuel containing fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs) with different molecular weights. The recent studies which are about the development of FAEE focused on production of FAEEs in vivo syntheses. This synthesis is catalyzed by wax ester synthases (WS). Bifunctional wax ester synthase/acyl-coenzyme-A (acyl-CoA): diacylglycerol acyltransferase (WS/DGAT) synthesizes wax ester by processing a certain range of fatty alcohols and fatty acyl-CoAs. It is considered as the final enzyme in biosynthetic process of wax ester production. Aim of the research is cloning, heterologous expression, purification and crystallization trial of was ester synthases from M. aquaeolei VT8 (MaWES) and R. opacus PD630 (RoWES). MaWES was cloned into pET expression vector and heterologous expression of MaWES was carried out in E.coli BL21 (DE3) strain. Three chromatography systems were used for purification of MaWES. After Immobilized Metal Affinity Chromatography (IMAC), buffer exchange and gel filtration chromatography, enzyme was purified with approximately 100 mg yield. This project can pave the way for structural studies WS/DGAT enzymes mentioned above. In summary, the findings of this study will circuitously help for solving the relationship between function and structure of these enzymes. It may lead to increased generation of FAEE based biodiesel.