Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
Browse
2 results
Search Results
Master Thesis Adsorption Kinetics of Methane Reformer Off-Gases on Aluminum Based Metal-Organic Frameworks(Izmir Institute of Technology, 2017) Angı, Deniz; Özkan, Seher Fehime; Çakıcıoğlu Özkan, Seher Fehime; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyOver the last decades, with the development in industrialization, the combustion of fossil fuels has generated an increasing level of emission of greenhouse gases into atmosphere. Considerable efforts have been endeavored to advance alternative cleaner energy source to relieve the stress on environmental concerns and depletion of oil reserves. Hydrogen is regarded as an ideal clean energy carrier. A great majority of ultrapure hydrogen is produced by hydrogen rich steam methane reformer (SMR) off-gas mainly composed of 60-80% H2, 15-25% CO2, 3-6% CH4 and 1-3% CO, which severely requires an efficient separation and purification process associated with gas adsorption principle. A novel class of porous adsorbents known as metal-organic frameworks (MOFs) represent outstanding separation performance due to possessing large surface area and tunable pore size. Aluminum based metal organic frameworks (Al-TPA) are widely utilized in gas separation/purification applications due to its breathing characteristics by adjusting cell volume reversibly. The highest surface area of Al-TPA was found to be 1270 m2/g by performing solvothermal synthesis route. Diffusion studies of SMR off-gas components on the Al-TPA were carried out at different flow rates (80, 168 and 175 mL/min), temperatures (34, 70 and 100 °C) and concentrations (15 and 28%). High value of parameter L demonstrated that system was under kinetic control. The diffusivity values were found to be ranging from 5.73 x 10-13-8.04 x 10-13 for CO2, 5.03 x 10-13-6.64 x 10-13 for CH4, 1.36 x 10-12-1.56 x 10-12 for H2 and 1.01 x 10-13- 5.03 x 10-13 m2/g for CO respectively with increasing temperature.Master Thesis Adsorption of Methane Reformer Off-Gas Components in a Column Packed With Cu, Al,ti and Zn Based Organic Frameworks(Izmir Institute of Technology, 2016) Kanaltı, Gaye; Özkan, Seher Fehime; Çakıcıoğlu Özkan, Seher Fehime; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyWithin the past decade, CO2 emissions from fossil fueled power plants has accelerated rapidly as a result of the increase in energy consumption associated with industrial development all over the world. Beyond the necessity of reduction in CO2 emissions, concerning on the crude oil reserves depletion induced the urgent need of transition to more efficient, renewable, cleaner and cheaper fuel, hydrogen. In the world, most of the hydrogen is produced by hydrogen-rich stream methane reformer (SMR) off gas streams composed of 80-60% H2, 15-25% CO2, 3-6% CH4 and 1-3% CO, thereby separation of SMR components became more of an issue. In this study, adsorption based separation of SMR components were investigated in a column packed with copper (CuTPA, (SLang: 776 m2g-1)), aluminum (AlTPA, (SLang: 1330 m2g-1)), titanium (TiTPA, (SLang: 1835 m2g-1)) and zinc (ZnTPA, (SLang: 1023 m2g-1)) based organic frameworks (MOFs). The pure gas adsorption studies on equimolar CO2/H2, CH4/H2 and CO/H2 systems and the equimolar mixture of CO2/CH4 system were carried out and the experimental breakthrough curves were obtained at three different feed flow rates (10, 20 and 30 mL/min) at three column pressure (1, 5 and 10 bar) at 303 K. The highest adsorption capacities of all MOFs were achieved at 30 mL/min of feed rate and 10 bar operating pressure, at these conditions the non-adsorptive behavior of hydrogen on the aforementioned MOFs was ensured. The amounts of CO2 adsorbed were calculated as 1.61, 5.54, 5.20 and 2.11 mmolCO2/g, while adsorbed CH4 amounts were 1.50, 3.16, 3.25 and 1.90 mmol CH4/g and the adsorbed CO amounts were 1.47, 2.59, 1.91 and 1.83 mmol CO/g on CuTPA, AlTPA, TiTPA and ZnTPA, respectively. The highest selectivity for CO2 over CH4 was attained on TiTPA as 8.0 at 10 mL/min feed rate of CO2/CH4 mixture at atmospheric column pressure and 303 K. The experimental adsorption isotherms of SMR components were fitted well with Langmuir and virial models and the best fitted model parameters were evaluated for each MOF.