The release of coal nitrogen and sulfur on pyrolysis and partial gasification in a fluidized bed

A fluidized bed system was used to pyrolyse and partly gasify five coals ranging in volatile matter from 35 to 45 wt%. From analysis of the original coals and the chars and tars produced, the partition of the coal substance, coal nitrogen and coal sulfur between char, tar and gases on pyrolysis and between char and gases on partial gasification was determined. On pyrolysis, coal sulfur was preferentially partitioned towards volatile products, the degree of enhancement depending partly on the pyritic sulfur content of the coal. For the coals studied, the proportion of the coal sulfur volatilized on partial gasification could be related to the coal substance gasified, using one equation for all the coals. For coal nitrogen however, a single equation described the data from both pyrolysis and partial gasification. (C) 1997 Elsevier Science Ltd.