Research of coal‐direct chemical looping hydrogen generation with iron‐based oxygen carrier modified by <scp>NaAlO<sub>2</sub></scp>
Bibliographic record
Abstract
Abstract This study reports a high‐performance modified oxygen carrier (OC) in a three‐cycle chemical looping process in which coal is used as the raw feedstock to produce hydrogen. A series of experiments of coal‐direct chemical looping hydrogen generation (CLHG) were conducted in a batch fluidized bed reactor, in the absence or presence of the NaAlO 2 . The experimental results indicated that the carbon conversion and hydrogen yield reached 87.0% and 1.30 L · g −1 , respectively, when the coal/oxygen carrier (Fe4Al6) mass ratio was 1:20. However, FeO was the main product of the reduction process with Fe4Al6, which limits the production of hydrogen during steam oxidation. Therefore, NaAlO 2 was used to improve the reaction performance of the OC. The carbon conversion and hydrogen production of NaAlO 2 ‐loaded oxygen carriers were 10.7% and 9.6% higher than Fe4Al6, respectively. X‐ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer‐Emmett‐Teller (BET), and temperature‐programmed reduction (TPR) techniques were used to characterize the oxygen carriers. According to the XRD analysis results, the addition of 5 wt% NaAlO 2 can generate NaFeO 2 . The unique layer structure of NaFeO 2 can loosen the structure between Fe 2 O 3 and Al 2 O 3 . Thus, the surface morphology and pore structure of the oxygen carrier were improved, which are responsible for the enhancement in reactivity rather than the catalytic effects of the alkali metal. The cycle performance of the Na0.5Fe4Al6 remained stable after multi‐redox cycles, and no serious sintering phenomena were observed; in addition, the carbon conversion and hydrogen yield remained above 86% and 1.40 L · g −1 , respectively.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".