Hydrogen from an Internally Circulating Fluidized Bed Membrane Reactor
Bibliographic record
Abstract
A novel fluidized bed membrane reactor has been developed for the production of high-purity hydrogen based on steam methane reforming (SMR). The reactor incorporates perm-selective membranes for in-situ removal of hydrogen from the reactor, thus shifting the thermodynamic equilibrium of the SMR reaction. The membranes also eliminate the need for downstream hydrogen purification.The endothermic reaction duty is provided either by external heating of the vessel wall or through direct air injection into the fluidized catalyst bed (autothermal reforming). The gas flow pattern within the fluidized bed induces internal circulation of catalyst particles between the central reaction (permeation) zone and outer heating zones. The circulating hot catalyst particles from the oxidation zone carry the required endothermic heat of reaction for the reforming while ensuring that the palladium membranes are not exposed to high temperatures or to oxygen. Another characteristic of the reactor configuration is that very little of the nitrogen present in the oxidation air reaches the reaction zone, thus maintaining the hydrogen driving force for the perm-selective membranes.The reactor concept was proven in a pilot reactor (0.13 m diameter, 2.3 m tall). A number of variables were studied, including steam-to-carbon ratio, temperature and pressure. The pilot reactor was operated with both external heating and direct air addition. Pure hydrogen (99.999+%) was obtained from the reactor and an equilibrium shift was demonstrated. The maximum pure hydrogen recovery obtained from the pilot reactor was 0.96 mol H2/mol CH4, limited by the installed membrane surface area for these tests.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".