In order to study nitrogen release from different nitrogen structures during coal pyrolysis, two model coals containing pyrrolic or pyridinic nitrogen have been prepared using cellulose and phenolic nitrogen compounds. Nitrogen release during pyrolysis of the model coals without and with catalyst has been studied in a fixed-bed reactor at 50 degreesC/min up to 1000 degreesC. The pyrolysis results show that HCN rather than NH3 is formed from the decomposition of pyrrolic and pyridinic nitrogen, and iron catalyst is effective on nitrogen removal for pyrrolic and pyridinic nitrogen. It is especially noteworthy that calcium catalyst also promotes nitrogen removal significantly from both pyrrolic and pyridinic nitrogen. (C) 2000 Elsevier Science Ltd. All rights reserved.