Direct growth of SAPO-34 crystals on ɣ-Al2O3 microspheres: A designated catalyst for fluidized-bed reactors of methanol conversion to light olefins
Bibliographic record
Abstract
Although intense research has been allocated to improve the SAPO-34 catalyst and mitigate its fast deactivation, the catalyst shaping for fluidized-bed application has rarely been studied. The conventional spray drying method (SiO 2 as the binder) downgraded the properties of the parent catalyst (i.e., caused 35% loss in active sites and 17% reduction in micropore surface area) and displayed an almost 30% shorter lifetime. Hence, a novel technique for in-situ growth of SAPO on the ɣ-Al 2 O 3 microspheres was developed utilizing hydrothermal microwave heating . SAPO loadings of 31 and 44 wt% with different morphologies (cubic and sheet-like particles) were achieved using two different templates (TEAOH and TEA). Both SAPO-mounted ɣ-Al 2 O 3 catalysts illustrated longer lifetimes (10.5 h and 22 h) during the MTO reaction at 425 °C with good light olefin selectivity (LOS ∼ 75%) compared to their parent SAPO counterparts (9.5 h and 15 h) and spray dried catalyst (7 h with LOS = 73%). The results are promising and serve as a basis for further investigation of the applicability of the new catalyst material in circulating fluidized bed reactors with simultanious regeneration.
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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) | 0.000 | 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) | 0.001 | 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".