Fe₂O₃/TiO₂ oxygen carrier for chemical looping combustion of CO, H₂, and CH₄ in a fluidized bed reactor

The high amount of CO₂ has been released to the atmosphere and causes severe environmental issues related to global warming and climate change. Carbon capture and storage (CCS) technology, including chemical looping combustion (CLC), is considered as the promising strategy to reduce the cost of CO₂ separation, avoid the NOx increment, and increase the combustion efficiency. In this study, the 40 wt%Fe₂O₃/TiO₂ was prepared using the incipient wetness impregnation method for the application as an oxygen carrier. The oxygen carrier was reacted with coal and biomass gasified syngas composed of H₂, CO, and CH₄ in a fluidized bed reactor under various operating conditions. A higher reaction rate was achieved by the increment of superficial velocity, operating temperature, and the concentration of CO or H₂. With 25% CO, application of 1000 °C operating temperature resulted in a higher utilization value compared to 800 °C operating temperature. When CH₄ was applied in the system, the occurrence of hydrogen production and carbon deposition due to the decomposition interrupted the analysis and calculation process. The higher syngas concentration in the CLC test led to a greater reaction rate due to the better diffusion capability. However, the higher reaction rate caused blocking and sintering on the oxygen carrier and reduced the final utilization at the end of reaction. The test under 10 redox cycles, kinetics analysis, and proposed reaction mechanism were also carried out by this study.