Combined Effects of EDTA and Heteroatoms (Ti, Zr, and Al) on Catalytic Activity of SBA-15 Supported NiMo Catalyst for Hydrotreating of Heavy Gas Oil
Bibliographic record
Abstract
M-SBA-15 (M = Ti, Al, and Zr) materials with a Si/M ratio of 20 were synthesized using a direct synthesis method. M-SBA-15 supported NiMo hydrotreating catalysts with and without EDTA was prepared by an incipient wetness impregnation method. A EDTA/Ni molar ratio of 2 was used for catalysts with EDTA. The hydrotreating activities of these catalysts were measured using Athabasca bitumen derived heavy gas oil, and comparison was done with the performance of NiMo/SBA-15 and NiMo/γ-Al 2 O 3 catalysts. All catalysts were thoroughly characterized by BET, TPR, TPD, CO-chemisorption, XRD, XANES, HRTEM, ICP-MS, and 13 C NMR. Incorporation of Ti, Al, and Zr in SBA-15 framework results in an increase in the surface acidity and metal support interactions in otherwise neutral SBA-15 material. This increases the dispersion, and HDS, HDN and HDA activity of a NiMo/SBA-15 catalyst increases by 12%, 70%, and 22%, respectively, as in the case of a NiMo/Ti-SBA-15 (Cat-Ti) catalyst. EDTA addition helps in better redispersion of molybdenum during sulfidation/activation as indicated by HRTEM and CO chemisorption studies. A XANES Mo LIII-edge study for the oxide state of catalysts reveals that EDTA helps in the formation of a greater number of molybdenum in octahedral structures which are easily reducible during sulfidation as compared to molybdenum in tetrahedral structures. A power law based kinetic study indicates that addition of EDTA lowers the activation energy, which could be due to formation of a more favorable Type II NiMoS active site. The activity studies show that using EDTA increases the HDS, HDN, and HDA activity of a NiMo/M-SBA-15 catalyst by 18%, 36%, and 22%, respectively, as in the case of a NiMo/Ti-SBA-15/2EDTA (Cat-TiE) catalyst. Based on the results from different characterization techniques, the schematic is presented related to the effect of EDTA-Mo-support interactions on dispersion of active metals in catalysts. The results from characterization techniques are in parallel with catalytic activity which follows the order Cat-TiE > Cat-AlE > Cat-ZrE > Cat- Ti. However, the catalytic activity of Cat-TiE is almost comparable to that of a NiMo/γ-Al 2 O 3 catalyst and has the potential for superior hydrotreating catalyst.
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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".