Effects of Na₂CO₃/K₂CO₃ on Chemical Looping Combustion Using Fe₂O₃/Al₂O₃ as Oxygen Carrier

Abstract

Abstract The performance of the Fe 2 O 3 /Al 2 O 3 oxygen carrier modified by the alkali metals, Na and K, was studied by thermogravimetric analysis and in a laboratory‐scale fluidized‐bed reactor. Different factors, such as the alkali metal content, the alkali metal type, and the interaction between Na and K, were taken into account. Both Na and K had strong catalytic effects on the conversion of Fe 2 O 3 . A high K content caused serious agglomeration. Increasing the Na content led to slagging because of the low‐melting point solid solution. The possibility of agglomeration and slagging was reduced when Na and K were added together. The oxygen carrier with 1.5 wt % Na and 1.5 wt % K had better combustion efficiency and optimal thermal stability. Na and K could enhance the attrition resistance and prolong the lifetime of the oxygen carriers.