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 Technology
    Energy 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
    Development of a New Antiscalant for Minimization of Stibnite Scaling in Geothermal Binary Plants
    (01. Izmir Institute of Technology, 2021) Baba, Alper; Demir, Mustafa Muammer; Demir, Mustafa Muammer; Demir, Mustafa Muammer; Baba, Alper; 03.03. Department of Civil Engineering; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Demand for renewable and sustainable energy resources has been increasing in recent years due to the adverse effects of fossil energy resources (gases, oil, coal ect,) on human health and nature. Since geology properties of our country is rich in geothermal energy resources, there is a remarkable increase in plant capacities every year. Geothermal energy is the energy obtained from the fluid, gas, and steam that have been stored in reservoirs by carrying the heat energy accumulated in the rocks in the depths of the earth or surfaced along the discontinuity zones.The increase in the use of geothermal energy and the increase in the capacity of the power plants has also revealed the problem of scaling. The main cause of deposition are the decrease in solubility of minerals by a decrease in pressure and temperature upon pumping the geothermal brine up to the ground. Calcium carbonate, calcium sulphate, metal silicates (Mg, Fe) are the most widely accepted types of scaling. In recent years, antimony and arsenic sulfide scaling have been encountered in volcanic and metamorphic regions. Between these two types of scaling, antimony sulfide is mostly seen in the heat-exchangers and preheaters where the temperature drops suddenly. In this thesis, the antimony sulfide scaling formed in the geothermal power plant was synthesized in an autoclave reactor under specified conditions. Water-soluble polymers nominee for being antiscalants such as Poly (vinyl sulfonic acid), Poly (acrylamide-co-vinyl sulfonic acid), Poly (acrylamide-co-vinyl phosphonic acid), Alginic Acid, Natural antiscalants, Polyacrylic acid, and Polyvinyl alcohol were employed. The results suggest that polymers containing vinyl sulfonic acid and acrylamide likely shows remarkable progress in increasing the concentration of ions in decantate, particularly at low dosages. (≈5 ppm)