X-ray photoelectron spectroscopy determination of the forms the nitrogen in Tongchuan coal and its chars

Pyrolysis experiment is carried out with a coal from Tongchuan, China under 773 K and 1173 K for 7 minutes in an electric Muffle furnace. the N 1s spectra from pulverized Tongchuan coal and obtained chars are evaluated by X-ray photoelectron spectroscopy (XPS). The nitrogen in the coal is pyridine, pyrroles, quaternary nitrogen and nitrogen oxides. Dominating species is pyridine accounting for 37%, which is rarely observed. There is no nitrate in it. By heating coal in thin air atmosphere, quaternary nitrogen will be converted into pyridines and pyrroles nitrogen enriched in coal char. N-oxide in the coal is formed when it is exposed to air and emits as volatile during severe pyrolysis