Organosulfur Compounds in Sulfur-Rich Raša Coal

Abstract

The organosulfur compounds in the extract and pyrolysate of the unusually organic sulfurrich (11.4 wt %) Upper Palaeocene Ras ˇa coal have been identified by gas chromatography-highresolution mass spectrometry. The major organosulfur compounds (OSC) present in the extract are alkylated benzo[b]-and dibenzothiophenes and in the pyrolysates alkylated thiophenes and benzo[b]thiophenes. In addition, a large suite of sulfur-containing polyaromatics were identified, which sometimes contain more than one sulfur atom per molecule. The degree of alkylation of many homologous series was found to maximize at either three, four, or five alkyl carbons. The dominance of polyaromatic sulfur compounds is consistent with the relatively mature stage of the coal (R o ≈ 0.7%), and their abundance at this rank indicates that the initial peat must have been extremely organic sulfur-rich (atomic S org /C ratio ≈ 0.15). This together with the very low abundance of lignin-derived components in the coal pyrolysate indicates that Ras ˇa coal should not be considered a typical coal. Nevertheless, our results represent a starting point that can be used as a guide for analysis of other coals.

13C-NMR Study on Structure Evolution Characteristics of High-Organic-Sulfur Coals from Typical Chinese Areas

“…Specifically, the increase in aromatic CH 3 carbons is more pronounced in the first half of the bituminous stage, and the decrease in aliphatic CH 3 carbons is dominant in the second half of the bituminous stage.…”

“…The distribution of SHOS coals in the world is fairly limited. Croatia Raša coal is the representative with an incredible organic sulfur content of 11.4 wt % [3]. In addition, Spain Mequinenza lignite [4], New Zealand Charming Creek coal [5], India Tipong coal [6], and some coals from the Australia Gippsland Basin [7] are all SHOS coals.…”

“…The hydrothermal fluids that have caused highly elevated S in coal are generally of epithermal origin [20] or are closely related to volcanic activities both in the marine (e.g., submarine exhalation) and in the terrestrial environments [24]. On the other hand, the SHOS coals in some cases contain highly-elevated critical elements that have a great potential for industrial extraction and utilization (e.g., rare earth elements, Y, V, Se, Mo, U) [3,25,26].…”

Geochemistry of Croatian superhigh-organic-sulphur Raša coal, imported low-S coal and bottom ash: their Se and trace metal fingerprints in seawater, clover, foliage and mushroom specimens

“…Chou (1997) compared organic S in Chinese SHOS coals Guidin (up to 9.18%) and Yanshan (up to 10.3%), with Croatian SHOS Raša coal (10.5%). According to Sinninghe Damsté et al (1999), SHOS Raša coal is characterised by unusually high amount of sulphur (11.8%), which is largely present in the form of anomalously high level of organic S (11.4%). The authors concluded that Raša coal is not a typical coal, as the organic matter had not been derived from the higher terrestrial plants.…”

Identification of Sulfur- and Nitrogen-containing Organic Species in the Extracts from Pocahontas No. 3 Coal

“…However, such a nonseparable analysis cannot afford detailed information about molecular structures of NCOSs and SCOSs in coals. A series of NCOSs (Yu et al, 1999;Sumbogo Murti et al, 2002) and SCOSs (Sinninghe Damsté et al, 1999;Ekinci et al, 2002) were observed in liquid products from coal pyrolysis. Since coal liquid oil is generally obtained by coal liquefaction at temperatures higher than 400 ı C, the compounds they detected may be quite different from those originally present in raw coals.…”