Iron ore modified with alkaline earth metals for the chemical looping combustion of municipal solid waste derived syngas

The redox performances of iron ore (IO) modified with different alkaline earth metals (AEM) as oxygen carriers (OCs) were evaluated with thermogravimetric analysis (TGA) and fluidized bed reactor experiments for the chemical looping combustion (CLC) of municipal solid waste (MSW) derived syngas. AEM oxides (BaO, CaO, and Mg0) and AEM aluminates (BaAl2O4, CaAl2O4, and MgAl2O4) were systematically studied for their ability to promote the redox cycles performance of 10. Acid digestion, FESEM, and XRD analyses were conducted for the characterization of the OCs before and after redox reactions to investigate the promoting mechanism. It was found that the BaO-modified 10 demonstrated the best reactivity with the reduction rate of 2.04%/min, which was twofold that of the pristine 10. AEM oxides presented superior redox performance than AEM aluminates owing to their strong interaction with Fe2O3 with the formation of AEM ferrites. The formed CaFe2O4 and MgFe2O4 with spinel structure and BaFe12O19 with hexagonal structure, as a result of the interaction, facilitated the lattice oxygen mobility and improved the reactivity of the modified 10. This interaction also increased the sintering resistance, while the morphology of the 10 became more porous after redox cycles, which was also responsible for the improved performance during the long term CLC operation. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

The redox performances of iron ore modified with different alkaline earth metals as oxygen carriers for chemical looping combustion of municipal solid waste derived syngas were evaluated. It was found that BaO-modified iron ore demonstrated the best reactivity, and AEM oxides showed superior performance compared to AEM aluminates due to their strong interaction with Fe2O3.