Investigating the trigger mechanism of Shenfu bituminous coal pyrolysis

• The 3D periodic structure of bituminous coal (C 1328 H 1130 N 21 O 245 S 7 ) was developed. • The trigger mechanism of coal pyrolysis was determined by experiments and ReaxFF MD. • Gas generation mechanism was the trigger mechanism of coal pyrolysis. This work aims at exploring the trigger mechanism of Shenfu bituminous coal pyrolysis. Flash pyrolysis technique combined with gas chromatography-mass spectrometry (Py-GC/MS), thermogravimetric analysis (TGA) coupled with Fourier transform infrared spectroscopy (TGA-FTIR), and reactive molecular dynamic simulations (ReaxFF MD) were employed in elucidating the trigger mechanism of coal pyrolysis. The proposed coal model was C 1328 H 1130 N 21 O 245 S 7 , whose pyrolysis was simulated using ReaxFF MD. Simulation results showed that the pyrolysis process could be divided into activation, decomposition and recombination stages, which agreed well with the experimental weight loss. Based on evolutions of gas species, it was found that the generation of gases was caused by the cleavage of oxygen-containing groups during the activation stage. Simulation results with the unimolecular of Shenfu coal showed that the order of chemical bond cleavage was C-O-C