High performance of la‐promoted Fe₂O₃/α‐Al₂O₃oxygen carrier for chemical looping combustion

Abstract

Iron oxide supported oxygen carrier (OC) is regarded to a promising candidate for chemical looping combustion (CLC). However, phase separation between Fe2O3 and supports often occurs resulted from the severe sintering of supports during calcination, which leads to the sintering and breakage of Fe2O3 thus the decrease of redox reactivity. In this article, La‐promoted Fe2O3/α‐Al2O3 were used as OCs for CLC of CH4 and for the first time found that the OC with the addition of 18 wt % La exhibited outstanding reactivity and redox stability during 50 cycles of CLC of CH4. Such a superior performance originated from the formation of LaAl12O19 hexaaluminate (La‐HA) phase with not only small particle size but also excellent thermal stability at CLC conditions, which worked as a binder to prevent the phase separation thereby the sintering and breakage of active species α‐Fe2O3 were avoided during reaction. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2827–2838, 2017

Inhibited Phase Segregation to Enhance the Redox Performance of NiFe2O4 via CeO2 Modification in the Chemical Looping Process

“…The large amount of CO 2 emission as a result of excessively relying on the combustion of fossil fuels leads to global warming. , Some techniques, such as pre-combustion, post-combustion, and oxy-fuel combustion, have been studied for CO 2 capture and separation, which suffered from the high operating costs of gas separation processes. − The shortcoming of the above techniques could result in a significant decrease in the overall combustion efficiency and an increase in the price of the energy. As a new advanced CO 2 capture technique, chemical looping combustion (CLC) has been extensively investigated to avoid the costly gas separation. , In the CLC process, fuels are reacted with lattice oxygen provided by the oxygen carrier (OC) and the main products are CO 2 and H 2 O after the complete combustion.…”

Enhanced Hydrogen Generation for Fe2O3/CeO2 Oxygen Carrier via Rare-Earth (Y, Sm, and La) Doping in Chemical Looping Process

“…As for the doped CeO 2 as supports for active metal oxides in the chemical looping process, Bhavsar et al found that La-doped CeO 2 could increase the oxygen transfer capacity and improve the activity and recyclability of iron oxygen carrier. Moreover, La-doped Fe 2 O 3 /Al 2 O 3 can significantly improve the activity and recyclability for the chemical looping combustion (CLC) and partial oxidation of CH 4 by CO 2 due to the generation of La-hexaaluminate. , Hedayati et al . indicated that the metal oxides with Ce 0.9 Gd 0.1 O 1.9 as support were more active than those with CeO 2 in CLC, demonstrating satisfactory sintering and agglomeration resistance.…”

Insight in kinetics from pre‐edge features using time resolved in situ XAS

“…Materials such as perovskites and spinels are widely applied for this process, because of their stable oxygen storage capacity and high oxygen mobility . In a novel chemical looping application, Fe 2 O 3 /MgAl 2 O 4 spinel was used as an energy storage material and Ni/MgAl 2 O 4 as dry reforming catalyst, next to CaO/Al 2 O 3 as sorbent material for CO 2 capture.…”