Redox degrees of iron-based oxygen carriers in cyclic chemical looping combustion using thermodynamic analysis

Chen, Wei‐Hsin; Chen, Kuan Hsiang; Ubando, Aristotle T.; Lee, Wen Jhy; Chio, Man Hin

doi:10.1016/j.cej.2021.130834

Cited by 13 publications

(1 citation statement)

References 57 publications

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“…50 CRJ OC was evaluated in the discontinuous fluidized bed reactor for 12 h of operation, considering three typical redox cycles (t red = 60 s; t oxi = until stabilization) with the three fuel gases (H 2 , CH 4 , and CO) and in three temperatures (850, 900 and 950 °C). Based on the reduction and oxidation enthalpies presented in study by Chen et al, 51 the reactions in the FR can be classified as endothermic or exothermic, depending on the selected reducing fuel gas. However, the reaction in the AR is always exothermic due to the negative enthalpy of the oxidation reaction.…”

Section: Evaluation Of the Ocs In CL System�batchmentioning

confidence: 99%

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

Araújo Barros do Nascimento Santiago,

de Araújo Melo,

Adánez-Rubio

et al. 2024

Energy Fuels

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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.

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Section: Evaluation Of the Ocs In CL System�batchmentioning

confidence: 99%