Analysis of nitrogen-containing species during pyrolysis of coal at two different heating rates

The effect of heating rate on the conversion of nitrogen in coal to nitrogen-containing species during pyrolysis of coal was investigated. Two pyrolysis apparatuses were employed in this study. One was an infrared image furnace (IIF) which can heat a sample up to 1100 °C at a heating rate of 10 K/s. The other apparatus was a Curie-point pyrolyzer (CPP) whose heating rate was around 3000 K/s. Conversion of nitrogen in coal to HCN from CPP pyrolysis at 1040 °C was higher than that in the case of IIF pyrolysis at 1000 °C. On the other hand, IIF pyrolysis experiments at 1000 °C produced large amounts of N₂ from low rank coals. The results indicate that heating rate can be one of the dominant factors affecting the behavior of nitrogen release as a range of heating rate applied in this study. The pyrolysis of a nitrogen-containing model polymer showed similar behavior to coal pyrolysis.