Twelve kinds of coal ranging from 66.1 to 89.5%daf of carbon content were rapidly pyrolyzed in a free-fall pyrolyzer at atmospheric pressure under nitrogen, at temperatures up to 980°C and heating rates of 4000-6000°C/s. The results show that another parameter is necessary to correlate the extent of organic sulfur removal from solid phase in addition to the carbon content. The extent of organic sulfur removal changed depending on the samples ranging from 70 to 80% of carbon content, and the difference of more than 30% was observed for the same carbon content samples: PSOC830 and Muswell Brook.
Sequential changes were observed in the sulfur form distribution of gravity concentrated samples having different contents of maceral group during rapid pyrolysis. The low specific gravity samples concentrated exinite and vitrinite. The release rate of organic sulfur from the solid phase increased linearly with the contents of exinite and vitrinite though the slope depended on the raw coals. The extents of organic sulfur removal also increased with the contents of exinite and vitrinite. The maceral group played an important role on the release of organic sulfur from the solid phase during rapidpyrolysis.