Introduction Chemical Looping Reforming (CLR) of Methane is using metal oxide as oxygen medium to partially oxidize methane for syngas production. Metal oxides are reduced by CH4 and fully reoxidized by air in another reactor. In this research, NiO-Fe2O3/La0.8Sr0.2FeO3 was synthesized as oxygen carrier and CO2 was utilized before air step to gasify coke and partially oxidize reduced particle. During CH4 step, CH4 was further introduced to the reduced particle and decomposed to produce H2 and coke. Bimetallic phases of NiO-Fe2O3 were combined into singular phase of NiFe2O4 through continuous cyclic redox and the activity of particle was gradually increased. Introducing CO2 could increase syngas yield and reduce minimal amounts of air to fully regenerate reduced particle. Result and Discussion Chemical Looping Reforming with Decomposition (CLRD) During CH4 step, CH4 was partially oxidized and produced CO & H2 with a little amount of CO2 at the early stage. The production ratio of H2 to CO was over 2 because parts of CH4 was decomposed with coke deposition. In the CO2 oxidation step, most of CO2 was reacted with deposed coke and reduced particle and produced CO. The reduced particle was fully reoxidized by O2 step with complete removal of the coke. After one looping process, CH4 was introduced once again for next cycle. The conversion of CH4 and CO2 increased through cyclic process. Structure of the particle. XRD patterns of fresh particle shows that part of NiO-Fe2O3 were combined to one single phase of NiFe2O4 through 10 redox cycle. This demonstrates that the mixed transition metal phases were emerged through synthesis and continuous redox process. The synthesized oxygen carrier showed gradual improvement of performance because of the phase transition. Conclusions This work has investigated chemical looping reforming of CH4 with CO2 conversion using synthesized perovskite oxygen carrier. Adding NiO to Fe2O3 led to the formation of NiFe2O4, which could further increase crystallinity to enhance particle activity. CO2 can be utilized for the coke removal and showed high conversion. The combined oxidation by CO2 and O2 was effective to increase the syngas production rate. These results have demonstrated that the CLRD process with combined CO2 & O2 oxidation is a promising alternative process for simultaneous CH4 reforming and CO2 conversion.

CO2-utilized chemical looping reforming with phase transition of Fe2O3–NiO to NiFe2O4 in perovskite catalysts

253rd National Meeting (2017)

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