Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Butyl Esters Production From Canola Oil Over Heterogeneous Base Catalysts(01. Izmir Institute of Technology, 2021) Akın, Oğuzhan; Şeker, Erol; Şeker, Erol; Şeker, Erol; 01. Izmir Institute of Technology; 03.02. Department of Chemical Engineering; 03. Faculty of EngineeringIn this study, transesterification reaction of canola oil with butanol over calcium oxide alumina catalyst was investigated with varying butanol:lipid molar ratios, catalyst amount and reaction time. Catalysts were prepared with the single step sol-gel method, and the activity of synthesized catalysts were investigated for two different forms of catalysts as powder and structured form. In the case of powdered catalysts, at butanol:lipid molar ratios of 9 and 24 with 6 wt% of lipids as catalyst amount, leaded 32% and 45% butyl esters yield in 1 hour. On the other hand, ~70% butyl esters yield has obtained at butanol:lipid molar ratios of 48 and 60 for the reaction time of 1 hour, while 89% yield had achieved when the reaction lasted for 4 hours at butanol:lipid molar ratio of 48. The necessity of mild basic strength and high butanol:lipid molar ratio was found to obtain high butyl esters yield. At high butanol lipid ratios of 48 and 60, it was observed that glycerolysis reaction occurs and promotes reverse transesterification reactions in first 30 minutes of the experiments. In the case of structured catalysts, lower butyl esters yields than powder catalysts were obtained, yet they eliminated the need for catalysts separation step in the experiments. Reusability tests showed that catalyst activity has decreased due to calcium ion leaching in the first hour of reaction and kept its activity constant for the rest of the reaction.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 Biodiesel Production From Safflower Using Heterogeneous Cao Based Catalysts(Izmir Institute of Technology, 2012) Yalman, Emir; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, the activities of heterogeneous mixed oxide catalyst; calcium oxide on alumina was investigated in the transesterification of canola and safflower vegetable oils to produce biodiesel, i.e. methyl esters. The primary goal of this study is to understand the effect of calcination temperature and calcium oxide (CaO) loading on the conversion activity of calcium oxide on alumina in the transesterification of canola and safflower vegetable oils. The mixed oxide catalyst was prepared by a modified single step sol-gel method. Calcium oxide was chosen because of its well known basic property. This study shows that calcium oxide on alumina catalysts having high CaO dispersion, calcined at high temperature, gave high biodiesel yields even under the reaction conditions, such as low reaction temperature, 50 °C, 9 of methanol/Oil molar ratio, 6 wt. % of catalyst/oil, and also short biodiesel reaction time, such as 4 – 10 minutes in the transesterification of safflower and canola oils. Also, it was observed that 70% CaO/Al2O3 catalyst when calcined at 700 °C was the most active catalyst among all the catalysts prepared in this study. Moreover, the reusability of CaO/Al2O3 demonstrated that ~20 – 250 ppm of Ca was lost during the reaction and the amount of Ca cation leaching depended on the reaction time, CaO loading and the calcination temperature. Also, it was found that Ca cation loss occurred during the reaction did not hinder the activity of the catalysts, which was found by the reusing the catalysts for couple times. Besides, when the biodiesel yield was higher than 70%, the system was influenced by external mass transfer limitation.