Bimetallic Iron-Copper Composite Oxygen Carrier for Chemical Looping Combustion and Hydrogen Generation

• Main Authors: Jing-An Chen, 陳勁安
• Other Authors: Young Ku
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/99088004099977289633

碩士 === 國立臺灣科技大學 === 化學工程系 === 103 === This study focused on Fe2O3 and CuO because of better thermal stability and high reduction rates, respectively. The Fe-Cu mixed oxygen carrier had higher oxygen transport capacity and reduction rate. The suitable oxygen carriers were selected by optimizing performance for the applications of Chemical Looping Combustion (CLC) and Chemical Looping Hydrogen Generation (CLHG) process. In order to increase the reactivity for Fe-Cu based oxygen carriers with syngas, the effect of Fe2O3/ CuO ratios was to investigate in this study. The results showed that Fe2O3/ CuO was 3/1 having better redox reactivity. Besides, in order to increase the mechanical strength of Fe-Cu based oxygen carrier, the Fe2O3 and CuO were not only prepared with Al2O3 or TiO2 as inert support by mechanical mixing and pelletized by tablet machine but also the different sintering temperature was also investigated. The results showed that FCA3110-S0 and FCT3110-S0 pellets sintered at 1000oC had proper mechanical strength and better reactivity during 10 redox cycle. The CLHG process was conducted at the fixed reactor which the steam flow rate was to investigate in this study. The results showed that the steam concentration had more influence than intake gas velocity. Hydrogen generation was demonstrated to be feasible by steam oxidation with reduced FCA3110-S0 and FCT3110-S0 oxygen carriers which the reaction temperature from 600-1000oC in the fixed bed reactor. The results showed that there were two processes which had the significant influence the hydrogen generation rate, i.e., the thermodynamic equilibrium and the reaction kinetics. The hydrogen equilibrium was higher at a lower operating temperature. However, the reaction rate constant increased with the increase of temperature. Finally, the FCA3110-S0 oxygen carrier was more suitable than FCT3110-S0 oxygen carrier to produce hydrogen at lower temperature. Besides, the fixed reactor experiments also provided that the reaction temperature influenced not only the reaction rate constant, k, but also the driving force in steam oxidization of FCA3110-S0 and FCT3110-S0 oxygen carriers. The kinetics analysis indicated that the steam oxidization of FCA3110-S0 and FCT3110-S0 oxygen carriers can be described as 3-D phase-boundary controlled model. The reaction order, α and energy of activation found for steam oxidation of FCT3110-S0 oxygen carriers were 1.65 and 20.328 kJ/mol, respectively. The reaction order, β and energy of activation found for steam oxidation of FCT3110-S0 oxygen carriers were 1.13 and 40.423 kJ/mol, respectively.