Volatilization behavior of nitrogen compounds in coals during the pyrolysis at two different heating rates

The effect of heating rate on the conversion of nitrogen-containing species during pyrolysis of coal was investigated. Two pyrolysis apparatus were employed in this study. One was infrared image furnace (IIF), which can heat a sample up to 1100 degrees C at a heating rate of 10 degrees C/s. Another apparatus was Curie-point pyrolyzer (CPP), whose heating rate was around 3000 degrees C/s. Pyrolysis experiments were performed at around 1000 degrees C because the volatile yields -were similar between two pyrolysis systems. N-conversion as HCN (the nitrogen amount of HCN produced by coal pyrolysis was divided by nitrogen content of original coal) in the pyrolysis by CPP was higher than that in the case of IIF pyrolysis. On the other hand, IIF pyrolysis experiments afforded large amount of N(2) with low rank coals. The results indicate that the heating rate seems to be a very important factor affecting the behavior of nitrogen release.