Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Energy, Exergy and Enviromental Assessment of a Novel Multi-Generation System Fed by Biomass and Geothermal Energy Sources(01. Izmir Institute of Technology, 2022) Gökçen Akkurt, Gülden; Mohammadpourfard, Mousa; Gökçen Akkurt, Gülden; Mohammadpourfard, Mousa; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyEnergy is the one of the critical tools that ensure the development of the countries. Since almost no country is completely energy independent, it is very important for countries to use the available energy efficiently and to produce their own energy from renewable energy sources. Multi-generation systems combine various cycles and processes to produce number of outputs and valuable market products using one or multiple energy sources as input. By creating a multi-generation system powered by renewable sources can increase system efficiency and provide some additional outputs such as hydrogen, heating, cooling, and domestic hot water. In this thesis, a novel multi-generation system consisting of a biomass gasification cycle, a double-flash geothermal cycle, an Organic Rankine Cycle and a PEM electrolyzer subsystems, is proposed to increase the efficiency and energy production from biomass and geothermal energy sources instead of using a single source for a single output. The proposed system is analyzed in terms of energy, exergy, and environmental impact point of view. By performing parametric studies for biomass flow rate, turbine inlet temperature, and single-objective optimization, effects on thermodynamic behavior and environmental impact are investigated for subsystems and overall system. The best operating conditions are determined. The findings indicate that energy efficiency of the proposed multi-generation system is 75% higher than a double-flash geothermal power plant. Based on the parametric study, biomass mass flow rate is encountered as the most significant parameter, which caused an 11.7% increase in energy efficiency, and 225% increase in environmental impact cost.Master Thesis Hydrothermal Treatment of Biomass in Hot-Pressurized Water(Izmir Institute of Technology, 2015) Dadenov, Saken; Emrullahoğlu, Mustafa; Yüksel Özşen, Aslı; Yüksel Özşen, Aslı; Emrullahoğlu, Mustafa; 03.02. Department of Chemical Engineering; 04.04. Department of Photonics; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of TechnologyThe aim of this study is to observe conversion of cellulose, which is the main compound of biomass, into its building-block chemicals in hot-pressured water as reaction medium with no addition of organic solvents. Water in liquid state under temperature and pressure above boiling point and below the critical point (374. 15 ºC and 22.1 MPa) is called as hot-pressurized water (or sub-critical water). Nowadays the biomass has great attention across the World as renewable source of energy, at the background of the quickly growing energy demand, since it is widely available and cheap. This technology is totally environmentally friendly and uses water as a reaction medium. As well known, since plant biomass contains up to 50% cellulose, it was decided to use it as a model compound in this study. Decomposition of cellulose leads to formation of various compounds. Among them levulinic acid is the most attractive chemical. Moreover, this acid marked as “Top 12 Building Blocks” of most perspective chemicals and obtaining from biomass by hydrothermal treatment is not widely studied. During this study, different reaction parameters such as temperature, pressure, reaction time and external oxidizer addition were studied to clarify their effects on cellulose decomposition and product yields to achieve the highest selectivity of the desired product. Addition of H2SO4 led to increase cellulose conversion up to 73% at 200 oC with a H2SO4 concentration of 125 mM at 60 min reaction time. Under same conditions, the yield of levulinic acid was successfully achieved to 38% after 60 min.Master Thesis Chemical Composition Analysis of Agroindustrial Waste and Their Potential Usage in Bio-Ethanol Production(Izmir Institute of Technology, 2011) Üçüncü, Can; Tarı, Canan; Tari, Canan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyBetween the year 2000 and 2008 the amount of fruits and vegetables used in fruit juice industry were 4918400 tons in Turkey. Thus, % 15-30 of a fruit is pomace, high amount of pomace appears as waste in fruit juice industry every year. Some of these pomaces could be candidates as potential fermentation media for bioethanol production. The aim of this study was in first step the optimization of the hydrolysis conditions using statistical methods and then the selection of the best hydrolysate for bioethanol production using the fungus Tricoderma harzianum. In the optimization study the factors were temperature, time, solid liquid ratio and acid percentage whereas the responses were furfural, hydroxymethylfurfural, glucose, xylose, galactose, arabinose and total reducing sugar yield. According to the results of the screening process, the hydrolysis step was carried out at a temperature and time of 126 ï‚°C, 40 min for apricot pomace and 110 ï‚°C, 40 min for peach and apple pomace. In the optimisation step and levels of the other factors were enlarged. The highest reducing sugar yield during optimization was 31% for apple, 49.16% for apricot and 52.44% for peach pomace. These results indicated that these pomaces hold certain potential for bioethanol production. Three different incubators (CO2, static and non-static) were used for the fermentation process. Tricoderma harzianum grown aerobically in two different media (YPM and YNB) inoculated in apple hydrolysates was used in each incubator for bioethanol production. The highest ethanol production was 1.67g/L in non-static incubator with the culture grown in YNB media.Master Thesis Heterotrophic Bio-Oil Production From Microalgae(Izmir Institute of Technology, 2010) Çağlar, Emre; Bayraktar, Oğuz; Bayraktar, Oğuz; Bayraktar, Oğuz; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe purpose of the thesis is to investigate the parameters affecting heterotrophic production of microalga, Chlorella minutissima. The aim is to use crude glycerol, a waste product derived from biodiesel production, as a carbon and energy source for microalgal growth and examine the optimum growth conditions in chemostat mode, as well as the productivity of oil using FTIR based technique. The highest lipid productivity achieved was 1.04 gl-1h-1, at the temperature 250C, with the dilution rate of 0.25 h-1 and using a substrate concentration of 80 gl-1 in feeding medium. The lipid, protein and carbohydrate content at this conditions was 14.36%, 47.89% and 8.06%, respectively.