Master Degree / Yüksek Lisans Tezleri

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

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Subject: search.filters.subject.Hydrogen

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Now showing 1 - 4 of 4
  • Master Thesis
    Synthesis of Copper Based Metal Organic Framework for Separation of Co2/H2 at High Pressure
    (Izmir Institute of Technology, 2014) Çiçek, Ahmet Uğur; Özkan, Seher Fehime; Çakicioğlu Özkan, Seher Fehime; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study, synthesis of Copper based metal organic framework (CuTPA) was achieved. Terephthalic acids were used as an organic linkers supplied from PETKİM A.Ş. Synthesis procedure was carried out in three steps; crystallization, purification and activation with different parameters. Crystallization time and temperature, purification method and solvent type , thermal activation rate are studied. MOFs were characterized by using SEM (Scanning Electron Microscopy), Fourier Transformer Infrared (FTIR), Thermal Gravimetric Analyzer (TGA), X-ray Diffractometer (XRD), and Volumetric Adsorption Instrument (ASAP 2010). The CuTPA with the highest specific surface area (SLang=776 m2/g) was synthesized after purification with methanol by soxhlet method in a schott bottle for 24 hours at crystallization temperature of 110 oC. Copper based MOF synthesized (SLang=776 m2/g) and Commercial NaX zeolite (SLang= 1359 m2/g) were packed in the column. Dynamic adsorption behavior of adsorbents was also studied; breakthrough of CO2/H2 and gases from the packed bed were carried out under total molar flow rate of 10, 20, and 30 mL/min gas mixture at 1, 5, and, 10 bars. It was conclude that the adsorption data results obtained from our system is reliable. As a result of breakthrough experiment both adsorbents (CuTPA and 13X zeolite) did not adsorbed H2. The break points are increased with increasing pressure and decreasing total flow rate. The amount to be adsorbed by the adsorbent in the column is increased indicating that the adsorption mechanism, controlling mechanism is changed with decreasing total flow rate.
  • Master Thesis
    Hydrogen Production From Water Using Solar Cells Powered Nafion Membrane Electrolyzers
    (Izmir Institute of Technology, 2007) Aksakal, Ziya Can; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The aims of this thesis are two folds; to construct single and multi cell proton exchange membrane electrolyzers and to evaluate the performance of these electrolyzers powered by solar panels on Iztech campus. All other parts, except the purchased membrane electrode assemblies, were designed, manufactured and assembled in our labs.In the construction of single and multiple cell proton exchange membrane electrolyzers, Nafion-117 based membrane electrode assemblies were used. Graphite bipolar plates, end plates, current collectors and gaskets were machined on institute.s computer numerical controlled lathe. In the first stage, a single cell electrolyzer with 20cm2 available electrolysis surface areas was examined with a direct current power supply by varying current density (0-500mAmp/cm2), water flow rate (0.05 to 0.5g/cm2min), and temperature (30-50oC). It was found that average cell voltage decreases from 2.18V at 30oC to 1.97V at 50oC when the current density is 500mAmp/cm2. Since cell gaskets were softened and stick to the membrane above 50oC of operating temperature, temperatures higher than 50 oC could not be tested. Five cell electrolyzer stack was constructed according to the final single cell design. It was observed that the stack could generate 388ml/min hydrogen under 500mAmp/cm2 and 10.09V of the operating condition at 41.5oC. When the stack was directly coupled with a solar array, voltage of the stack was found to vary from 7.5V to 12.5V and the current density changes from 0 to 1000mAmp/cm2 with respect to the solar radiance of the day. This results in a voltage efficiency ranging from 98.7% to 60% based on the higher heating value of hydrogen. Electrolyzer powered by solar cells can generate up to 750ml/min hydrogen and total daily production could be as high as 350L per day but weather condition greatly affects the production rate. Together with the losses inside the electrolyzer, another important energy loss is due to voltage mismatches between PV array and electrolyzer in low solar irradiance during sunrise and sunset.
  • Master Thesis
    Determination of Preparation Conditions for Membrane Electrode Assembly of Pem Electrolyzer
    (Izmir Institute of Technology, 2013) Düzgören, Derya; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The aim of this thesis is to investigate the effect of preparation conditions of Membrane Electrode Assembly (MEA) on the hydrogen production of a single cell Proton Exchange Membrane (PEM) electrolyzer operated at room temperature and atmospheric pressure. In the first part of the thesis, the catalyst ink, without the metal catalysts, coated membrane (MEA), with the 16 cm2 active area, were produced. For the proton exchange membrane Nafion-117 membrane was used. An experimental design (Small Central Composite Design) was done in order to investigate the optimum preparation conditions (such as temperature, pressure and holding time in the hot press) for MEA of PEM electrolyzer. The responses were water vapor permeability and the surface resistance of the catalyst ink coating. The optimum conditions that gave maximum permeability and lowest surface resistance were found at 135°C of the hot press temperature, 5000 pound of pressure and 3 minute of holding time. In the second part, Membrane Electrode Assembly containing Pt and Pt/Ru metals in the catalyst ink was produced using the optimum conditions found in the first part. Then the prepared MEA was compared with the commercial MEA containing Pt and Pt/Ru metals using our home made single PEM electrolyzer.
  • Master Thesis
    Analysis of a Hydrogen Fueled Internal Combustion Engine
    (Izmir Institute of Technology, 2005) Kahraman, Erol; Özerdem, Barış; Özerdem, Mehmet Barış; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In the history of internal combustion engine development, hydrogen has been considered at several phases as a substitute to hydrocarbon-based fuels. Starting from the 70.s, there have been several attempts to convert engines for hydrogen operation.Together with the development in gas injector technology, it has become possible to control precisely the injection of hydrogen for safe operation. Since the fuel cell needs certain improvements before it is widely used in vehicles, the conventional internal combustion engine is to play an important role in the transition. This study examines the performance characteristics and emissions of a hydrogen fueled conventional spark sparkignition engine. Slight modifications are made for hydrogen feeding which do not change the basic characteristics of the original engine. Comparison is made between the gasoline and hydrogen operation and engine design changes are discussed. Certain remedies to overcome the backfire phenomena are attempted.