Fe–Mn based minerals with remarkable redox characteristics for chemical looping combustion

Microstructural Stability of Tailored CaMn0.875−xFexTi0.125O3−δ Perovskite Oxygen Carrier Materials for Chemical Looping Combustion

“…Ther edox cycles at 950 8Cu nder H 2 and CH 4 atmospheres are shown in Figure 9a,b.T he conversion of the material is normalized to the total oxygen capacity.Initially,t he material is fully oxidized in air, that is,t he initial normalized material conversion is 0%.T he conversiono ft he material at 100 %c orresponds to the full release of its total oxygenc apacity.F or all compositions,i tt akes two cycles for the material and the instrumental setup to reach an ew dynamic equilibrium.T he reduction and oxidation reaction rates were derived from the maximum tangent slope of the followingc ycles,a sp reviously detailed. [7,8] These results are reportedinF igure 10. Remarkably,t he responset oc hanges in the atmosphere is notably shortened for the samples containing iron.…”

“…For all compositions, it takes two cycles for the material and the instrumental setup to reach a new dynamic equilibrium. The reduction and oxidation reaction rates were derived from the maximum tangent slope of the following cycles, as previously detailed . These results are reported in Figure .…”

“…The procedure was similar to that described by Fossdal et al . and Larring et al . The reducing conditions were adjusted with 2 % steam (steam methane reforming/water–gas‐shift reactions) and 25 % CO 2 (dry reforming).…”

“…Furthermore, materials must be of low cost and low toxicity . From expensive nickel oxide to low‐costing ores, several hundreds of materials based on Ni, Cu, Fe, Mn, Co, and mixtures of these materials have been studied as potential OCMs for CLC . Lately, there has been significant interest in mixed transition‐metal oxides and complex perovskite‐type oxides, especially those derived from the calcium manganite CaMnO 3− δ family.…”

“…expensive nickel oxide to low-costing ores, [6][7][8] several hundreds of materials based on Ni, Cu, Fe, Mn, Co,and mixtures of these materials have been studied as potential OCMs for CLC. [9] Lately,t here has been significant interest in mixed transition-metal oxides [10] and complex perovskite-type oxides, [11] especially those derived from the calcium manganite CaMnO 3Àd family.F or CLC applications, substitution of calcium by strontium and barium [12] has been considered.…”