SH radical: the key intermediate in sulfur transformation during thermal processing of coal
- Chinese Academy of Sciences, Taiyuan (China). State Key Laboratory of Coal Conversion, Institute of Coal Chemistry
To uncouple the complex behavior of sulfur transformation during thermal processing of coal and to elucidate the main mechanism, typical organic and inorganic sulfur compounds impregnated on or mixed with a low-ash char are studied through temperature-programmed decomposition coupled with online mass spectrum analysis (TPD-MS) and followed by temperature-programmed oxidation coupled also with online mass spectrum analysis (TPO-MS) in a temperature range of up to 800{sup o}C. It is evident that the cleavages of C{sub al}-S and C{sub ar}-S bonds, where the subscripts al and ar stand for aliphatic and aromatic carbon, respectively, in the organic compounds result in the formation of SH radicals, which then undergo secondary reactions with the char to form various sulfur compounds such as H{sub 2}S, SO{sub 2}, COS, and elemental sulfur, as well as sulfur structures in the char. H{sub 2} has the ability to stabilize the SH radicals and weaken the interactions between the SH radicals and the char. For the sulfur compounds, which do not generate the SH radical, the only sulfur products detected are those formed directly from the decomposition of the starting sulfur compounds, H{sub 2}S from FeS{sub 2} in H{sub 2} or SO{sub 2} from Fe{sub 2}(SO{sub 4}){sub 3} in He, for example, and no sulfur structure is formed in the char. Minerals have significant effects on the bond cleavage temperature and the reactions of the SH radicals with the char. It is clear that the SH radical is a key species interacting with the char to form secondary sulfur compounds, while H{sub 2}S and SO{sub 2} play no role in the sulfur transformation to the carbon structure. 34 refs., 12 figs., 1 tab.
- OSTI ID:
- 20638441
- Journal Information:
- Environmental Science and Technology, Vol. 39, Issue 13; Other Information: zyl@public.ty.sx.cn; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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