Case study of igneous intrusion effects on coal nitrogen functionalities

This study presents the results of the nitrogen XPS analysis performed on a set of four Bukit Asam (Indonesia) low-rank coals and on a related natural pyrolysis product formed after an igneous intrusion. Low-rank coal nitrogen XPS sub-peak is dominantly pyrrolic, with subordinate quaternary and pyridinic. Dike intrusions are responsible for transformation of these nitrogen forms nitrogen to “graphitic” quaternary nitrogen. The transformation of nitrogen is similar to that exhibited by laboratory prepared pyrolysis products of other coals.

Research highlights► Nitrogen functionality of Bukit Asam coals. ► Igneous intrusions heat enhance coal pyrolysis and nitrogen transformation. ► Quaternary nitrogen increases in coal after in situ heating by igneous intrusions.