Evaluation of Brazilian Iron-Based Ore and Industrial Waste as Low-Cost Oxygen Carriers for Chemical Looping Process

Abstract

Given the crucial role of oxygen carriers in advancing chemical looping (CL) technology, the innovation of this study lies in the evaluation of inexpensive and readily available materials, specifically iron ores (Carajaś iron ore, CRJ) and residues from the steel industry in Brazil [mill scale residual (MSR), iron spill residue (ISR)], as yet unexplored oxygen carriers in this process. These materials were analyzed for their chemical composition, crystalline structure, and redox properties during reactivity testing on a thermogravimetric analyzer. Among all the materials, CRJ, MSR, and ISR exhibited the highest conversions with H 2 fuel gas. Notably, CRJ displayed a higher oxygen transport capacity (R oc = 3.92) and a higher Rate Index with CH 4 (RI CHd 4 = 13,94%/min and RI air = 12,01%/min). Consequently, this material was selected for testing in the discontinuous fluidized bed reactor under CL conditions, evaluating gaseous product distribution, mass loss rates due to attrition, particle agglomeration, and carbon deposition. CRJ demonstrated excellent fuel conversion and reactivity with H 2 (H 2 > CO > CH 4 ), and the conversion increased with temperature, reaching complete combustion in the initial period of reduction at 950 °C, achieving X red = 0.113 and X ox = 0.155, indicating complete regeneration. There was no carbon deposition, low attrition loss, and a stable lifetime of 15,000 h. It also maintained reactivity under hydrogen gas without agglomeration or defluidization issues. The findings of this study carry substantial implications for upscaling CL processes utilizing low-cost materials with promising attributes.

Hydrogen Production from Biomass-Based Chemical Looping: A Critical Review and Perspectives

“…Furthermore, the preparation of Fe-based OCs remains confined to laboratory research or small-scale testing phases. As an alternative, waste-based OCs have been proposed and favored for their low cost and feasibility of large-scale production, garnering considerable interest. − Nonetheless, these waste-derived OCs harbor significant impurities, which curtail their performance, necessitating additional processing to enhance their redox performance. , Achieving a satisfactory compromise between cost and performance in these waste-based OCs proves challenging due to their positive relationship. It is noteworthy that the overall expense remains lower than that of synthetically produced Fe-based OCs, which exhibit superior reactivity …”