| Summary: | 博士 === 國立臺灣科技大學 === 化學工程系 === 102 === Chemical looping process is a potential energy technology with inherent CO2 capture to provide superior energy efficiency than existing CO2 capture technologies. Oxygen carriers are applied for chemical looping process in place of air to offer oxygen for fuel combustion; therefore, to enhance CO2 purity in the effluent stream. Alumina supported Fe2O3 were prepared and demonstrated reasonable reactivity for Fe2O3/Al2O3 particles containing 60 wt% Fe2O3 and sintered at 1300 °C. FeAl2O4 was characterized by XRD after reduction and served as supporting material as well as oxygen carrier in practical operation. Hydrogen generation was demonstrated to be feasible by steam oxidation with reduced Fe2O3/Al2O3 oxygen carriers in a fixed bed reactor. Fe2O3/Al2O3 pellets were examined by crush strength and TGA demonstrated proper crush strength and reasonable reactivity as oxygen carrier for chemical looping process. Methane, isopropanol (IPA), polyurethane (PU) and polypropylene (PP) combustions are conducted by a moving bed fuel reactor using the prepared Fe2O3/Al2O3 oxygen carriers. Complete combustion of methane was achieved with oxygen carrier-to-fuel ratio higher than 1.14 at 900 °C. The oxygen carriers that moving out of the moving bed reactor were composed of mainly FeO and FeAl2O4, characterized by X-ray diffraction (XRD) analysis, indicating further utilization of oxygen in Fe-based oxygen carriers can be achieved by moving bed operation. For IPA combustion, CO and H2 were the fuel gases generated by IPA solution in the moving bed reactor prior to combustion with oxygen carriers. The IPA conversion and CO2 yield in the outlet stream from moving bed reactor reached 100% as oxygen carrier-to-fuel ratio was higher than 7.94 at 900 °C. By analysis of system processing capacity, 70% of output processing capacity is available for energy use of external facility. By analysis of processing efficiency, aqueous solution as liquid fuel would cause considerable heat consumption for water evaporation, especially for dilute solution. For PU and PP combustion, an annular duel-tube moving bed reactor (ADMBR) was used as fuel reactor for gasification and combustion of PU and PP particles. CO and H2 were the major components of fuel gas generated by gasification of PU and PP particles in ADMBR. Complete conversion of plastic particles and 100% CO2 yield of fuel gas were achieved as oxygen carrier-to-fuel ratio for PU and PP particles reached 3.10 and 10.94, respectively. The heat demands for ADMBR were calculated to be 21% and 52% of output processing capacity by heat consumptions of fuel gasification in the fuel reactor of CLC system, respectively. This study evaluated essential parameters on preparation of Fe2O3/Al2O3 oxygen carrier, operation of moving bed reactor and fuel combustion. Fe2O3/Al2O3 oxygen carrier was completely combusted fuels in the moving bed reactor; furthermore, the reduced Fe2O3/Al2O3 oxygen carrier was capable for hydrogen generation by steam oxidation. Hence, the prepared Fe2O3/Al2O3 composite was validated as oxygen carrier for chemical looping process.
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