Effect of sodium on three-phase nitrogen transformation during coal pyrolysis: A qualitative and semi-quantitative investigation

Alkali metals have a significant effect on the transformation of three-phase nitrogen during coal pyrolysis, but there is lack understanding about this mechanism action. In work, effects inorganic sodium (NaCl) and organic (CH3COONa) mutual in pyrolysis were studied by TGA-MS/FTIR, XPS Py-GC/MS. Results shown that more remained char, conversion heterocyclic to tar-N was inhibited with most CH3COONa lower addition NaCl, including transformations N-5 pyrrole-N amine-N, N-6 pyridine-N nitrile-N. While higher NaCl promotes char-N volatile-N. Sodium decreases yield tar, especially amine-N nitrile-N through promoting tar HCN NH3. Both promotion release inhibition are stronger than CH3COONa. The NaCl-added samples 2.69%–4.29% CH3COONa-added samples, while content 2.6%–18.6% samples.