Study on occurrence of organic sulfur in Xinyu clean coking coal by extraction and stripping

Xinyu clean coal rich in organic sulfur was chosen to study the distribution of organic sulfur with different structures in raw coal and its group components. Analysis techniques including X-ray photoelectron spectroscopy (XPS), gas chromatography/mass spectrometer (GC/MS), etc. and separation methods of extraction and stripping and fractional extraction were applied, with a focus on the occurrence of different organic sulfur in coal organic matter and its group components. The results show that there is a significant negative correlation between the occurrence ratio based on total sulfur in some group components and the structure complexity. The distribution of soluble sulfur-containing components in total dissolving-out substances is generally uniform, compared with that in each group component. Most soluble organic sulfur with conjugated structure is distributed over the dense medium component, but fewer in loose medium component, which is predominantly in the form of thiophene sulfur, and the fewest in heavy component. Soluble organic sulfur with aliphatic structure is mainly distributed over heavy component and dense medium component, but rarely in loose medium component. Evident additivity is observed in the extract yield of organic sulfur in each group component with the change of extraction time while the dissolution behaviors of soluble sulfur-containing components in the group component are mutual independence. This is consistent with the basic idea of coal inbuilt structure model. The occurrence of organic sulfur in coal follows the rule of similarity-intermiscibility.