Distribution of Organic-Sulfur-Containing Structures in High Organic Sulfur Coals

The distribution of organic sulfur-containing structures in two coals of high organic sulfur and low pyritic sulfur content was investigated using continuous isothermal flash pyrolysis experiments at 750 to 960°C. The conditions of atmospheric pressure and low contact times (<1 sec) minimized secondary reactions. The volatile sulfur-containing gas products (i.e., H 2 S, COS, and CS 2 ) were measured as a function of pyrolysis temperature and compared to the products from the pyrolysis of a range of model sulfur compounds. The results suggest that the transformation of sulfur in coal goes from the more labile pendent sulfur structures to the more stable heterocyclic sulfur structures as coalification proceeds.