Impact of Nonoxidized Sulfur Species on Elemental Mercury Removal by SO<sub>2</sub> Activated Petroleum Cokes
Bibliographic record
Abstract
High-sulfur petroleum coke is potentially one of the most promising materials for developing efficient and low-cost sorbents for Hg 0 removal from flue gas. In this study, three distinct SO 2 -activated high-sulfur petroleum cokes were prepared at 650–850 °C via different sulfurization protocols, including SO 2 -impregnated petroleum coke (PC-S), SO 2 -impregnated coke produced with an additional reductive heat-treatment process in N 2 (PC-NS), and SO 2 -impregnated coke prepared with the presence of SO 2 in the gas during the cooling process (PC-SC). The SO 2 -activated cokes were characterized with nitrogen adsorption/desorption measurements, X-ray photoelectron spectroscopy, thermogravimetric analysis, and their mercury removal performances were investigated in a fixed-bed reactor at 80–200 °C with an initial mercury concentration of 35–120 μg/m 3 . To explore the influence of nonoxidized sulfur species on Hg 0 removal, particular focus was given to the comparison of the reduced sulfur, sulfide sulfur, and elemental sulfur formed during different sulfurization processes, as well as the consequent differences in Hg 0 adsorption characteristics. It found that the sulfur incorporated into the carbon matrix of PC-S by interaction with SO 2 at 650 °C was dominantly organic sulfide. Thermal treatment in N 2 at 800 °C led to an addition of reduced sulfur in PC-NS. An increment of 0.74 at. % elemental sulfur was observed in PC-SC after exposure to SO 2 during the cooling step. The Hg 0 adsorption capacity of PC-SC at low temperatures was significantly enhanced, yielding a mercury capacity of 622 μg/g at 80 °C. However, elemental sulfur suffered from severe temperature sensitivity for mercury binding. The sample PC-NS which contained more reduced sulfur showed the highest Hg 0 adsorption capacity at elevated temperatures above 160 °C. Furthermore, the increment in inlet mercury concentration would lead to higher adsorption capacities and faster adsorption rates. According to the R L obtained from Langmuir isotherms, the Hg 0 adsorption reactivity can be arranged as follows: PC-NS > PC-S > PC-SC. The mercury temperature-programmed desorption results suggested that sulfur species not only had an effect on Hg 0 adsorption capacity but also played an essential role in the thermal stability of the adsorbed mercury compounds. Mercury was principally associated with elemental sulfur in the form of metacinnabar and combined with thermal-stable organic sulfide in cinnabar or organomercuric compounds Hg–SR.
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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".