Preparation and Characterization of Lanthanum-Promoted Copper-based Oxygen Carriers for Chemical Looping Combustion Process
Bibliographic record
Abstract
Chemical looping combustion (CLC) is an oxygen combustion process that results in the higher CO2 concentrations in flue gases. Copper-based oxygen carriers have high reactivity, resulting in high purity CO2 generation, but face the challenges of low copper melting point and potential thermal sintering under high-temperature cyclic operation. A temperature-programmed reduction and oxidation (TPR-TPO) technique (Redox) was used to simulate of the cyclic operation of copper-based oxygen carriers in the CLC process. Multiple material characterization methods were applied to the fresh and used oxygen carriers, including the determination of pore structure and surface area by Brunauer-Emmett-Telle (BET), crystal structure by X-ray diffraction (XRD) and surface phase diagram analysis by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDX). Thermally stable copper-based oxygen carriers have been successfully prepared using commercially-available Al2O3 as the supporting material and selected additives. A substantial resistance to agglomeration and durability in over 50 cyclic Redox tests under high temperature conditions (oxidation at 800°C and reduction at 800°C) has been confirmed for the Sample labeled as CLCA. The oxygen transfer capability was almost stable, and the CuO content ranged from 20 wt% to 23 wt% for the CLCA sample. The supporting material (Al2O3) significantly impacted the oxygen releasing performance and thermal stability of the copper-based oxygen carriers, due to the formation of a new crystal phase (CuAl2O4) which cross-links the CuO and the γ-Al2O3. Lanthanum accelerated the cross-linking between CuO and Al2O3.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".