Performance Evaluation of Sulfated-TiO<sub>2</sub> as a Modifier to Co−Ni−ZrO<sub>2</sub> Catalyst in a Dual-Bed Reactor for the Selective Production of C<sub>4</sub> Hydrocarbons from Syngas
Bibliographic record
Abstract
Modified Fischer−Tropsch (MFT) synthesis was performed at atmospheric pressure in a fixed-bed microreactor with a dual-bed configuration using Co−Ni−ZrO 2 and sulfated-TiO 2 solid acid catalysts. The sulfate loading in the sulfated-TiO 2 catalyst was in the range 5−15 wt % whereas sulfated-TiO 2 to Co−Ni−ZrO 2 catalyst mass ratio was 1−3. The catalyst system was activated by reduction at temperatures ranging from 573 to 723 K for 16 h whereas sulfated-TiO 2 catalyst was calcined at temperatures in the range 723−923 K for 4 h. MFT reactions were performed at weight hourly space velocities (WHSV) in the range 5−20 h - 1 and reaction temperatures ranging from 513 to 533 K. Though these parameters did not have substantial effects on the hydrocarbon product composition, the optimum selectivities for C 5 + hydrocarbons, i -C 4 hydrocarbons, and C 2 −C 4 olefins from syngas using Co−Ni−ZrO 2 due to the presence of the modifier sulfated-TiO 2 were increased from 26 to 31 wt %, 2 to 4 wt % and 34 to 44 wt %, respectively. However, the presence of sulfated-TiO 2 catalyst had no substantial effect on the selectivity for total C 4 hydrocarbons. Though the sulfated-TiO 2 catalysts possessed large amounts of acid sites, these sites were weak, and as such, could only catalyze reactions such as isomerization, oligomerization, dehydrogenation and alkylation. The more demanding cracking reactions could not be promoted on sulfated-TiO 2 catalysts. The weak acidity exhibited by sulfated-TiO 2 catalysts is an asset in that it was able to maintain activity stability for a long period of time in contrast to the performance of sulfated-ZrO 2 catalysts, which deactivated rapidly because of its strong acid sites.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| 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".