Behaviour of sulfur in high-sulfur coal in a superacidic medium without gaseous hydrogen

The Comparison of Oxygen and Sulfur Species Formed by Coal Oxidation with O2/Na2CO3 or Peroxyacetic Acid Solution. XPS Studies

“…Figure shows typical XPS spectra of S 2p for the studied coal samples: dem L and Cz, as well as L and Cz oxidized by O 2 /Na 2 CO 3 or PAA which represent highly and moderately oxidized samples. The fitting of S2p peaks (without fixing either positions or half-widths) gave the following binding energies: 163.6 ± 0.1, 165.1 ± 0.2, and 168.0 ± 0.3 eV which correspond respectively to sulfides + thiophenes + thioethers + mercaptans, , sulfoxide C−SO−C, , or sulfones C−SO 2 - C . The first and the third peak are in a very good agreement with literature and the second in a reasonable one; however, it must be added that no constriction on the binding energy was used in the fitting program.…”

“…Thus surface studies of coal are especially interesting, and XPS has a unique role to play in that respect. XPS has been used to determine forms of sulfur in different types of coals: Argonne Premium coals, Spanish coals of Mequinenza, , Utrillas and Calaf basins, Australian coalsGreta and Whybrow seams, Sydney Basin, and Moranbah Measures in Bowen Basin, or Chinese coals from Guizhou Province . Both aliphatic and aromatic sulfur was found in coalsthe levels of the latter increasing directly as a function of increasing rank. ,, It was also found that the aliphatic sulfur oxidized in air more rapidly than aromatic sulfur. ,, Aliphatic sulfides were found to be converted to oxidized forms (sulfoxides, sulfones, sulfonic species) during oxidation in air at 125 °C as shown by XPS and XANES for Rasa, Charming Creek, and Mequinenza coals …”

The effects of indigenous minerals in a coal on the emissions of NO and SO2 during combustion

“…In the work described here, the effects of indigenous minerals in coal from China on the emissions of NO and SO 2 during coal combustion were investigated using a thermogravimetric analyzer which has been used to investigate the behavior of adsorbents through the measurement of emissions, enabling some valuable conclusions to be drawn [3][4][5]. [6][7][8] Coal from Tongchuan in China was used. The proximate and elemental analyses and the ash analysis for this coal are listed in Tables 1 and 2.…”

Desulfurization and Solubilization of High-Sulfur Coal by Superacid HF/BF3

“…Strong acids have been reported to depolymerize coal in milder reaction conditions. − The high acidity of superacids can be expected to desulfurize and solubilize coal catalytically and also contribute to deoxygenation and desulfurization of coal in the presence of hydrocarbons or hydrogen pressure at 150−300 °C. We previously reported that a liquid or gaseous Brönsted superacid, trifluoromethanesulfonic acid (TFMS), HF, and HF/BF 3 depolymerized and desulfurized coal significantly at 100−150 °C without gaseous hydrogen. − The Brönsted acid, HF, is a frequently used alkylation catalyst for converting light olefins into gasoline components. The acidity of the mixture of HF/7 mol % BF 3 (Ho = −16.6) is much higher than that of TFMS (Ho = −14.6), leading to higher activity of the former as an acid catalyst .…”