Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Petrol ve Doğal Gaz Mühendisliği Bölümü, Türkiye
Tezin Onay Tarihi: 2010
Öğrenci: ECE HATİCE TOPA
Danışman: MUSTAFA VERŞAN KÖK
Özet:Application of thermogravimetric analysis to the renewable energy sources is a novel study and it has been becoming attractive by the researchers in recent years. In this thesis, thermal and kinetic properties of biodiesel as new energy source, diesel and canola oil have been analyzed by using very popular thermogravimetric analysis methods which are; Differential Scanning Calorimetry (DSC) and Thermogravimetry (TGA/DTG). The main aim of the study is to observe the combustion and pyrolysis behaviour of methanol route biodiesel and diesel blends at different blending rates. Additionally, combustion and pyrolysis behaviour of canola oil, the origin of biodiesel have been analysed to observe the transesterification reaction effect on biodiesel. Therefore, biodiesel, diesel, canola oil and blends of diesel and biodiesel at different percentages are exposed to isothermal heating under nitrogen and air atmosphere with a constant heating rate of 5, 10 and 15˚ C/min by using TGA/DTG and DSC to 600˚C. According to combustion thermograms of pure samples, it is observed that combustion temperatures of the samples taking place are in the order of canola oil>biodiesel>diesel, implying that the transesterification reactions are making the triglyceride molecules more ignitable. However, diesel molecules consisting of hydrocarbon chains still have lower ignition temperature than biodiesel. Also, it is found that as the heating rate of the reactions increase, peak temperatures of the reactions shift higher; implying that as the heating rate of the reactions increase reaction lose their sensitivity. According to the combustion thermograms of mixtures of the diesel-biodiesel mixtures, it is understood that B15 has better combustion properties combustion of B15 occurs at lower temperatures and has the highest exothermic enthalpy. When the pyrolysis mechanisms of the pure samples are analyzed, it is noticed that the stability of the samples are in the order of canola oil>biodiesel>diesel, which means that transesterification reactions make the samples less stable. As the content of the biodiesel in the mixture of diesel-biodiesel increase, the stability of the samples increases. By using some of the equations derived in literature, ignition temperatures and heat capacitances of the samples are calculated. Ignition temperatures of biodiesel, diesel and canola oil are 141.1, 108.7 and 209.5 ˚C, respectively and heat capacitances are in the order of; diesel>biodiesel>canola. In addition to that several kinetic methods have been applied to determine the pyrolysis and combustion reaction parameters of the reactions. Activation energies of the samples are in the order of canola oil>biodiesel>diesel and for the different heating rates of reactions it is noticed that the activation energy is sensitive to the heating rate of the reactions and they are in the order of 5˚C/min>10˚C/min>15˚C/min.