Raman spectroscopic study on the pyrolysis of Australian bituminous coal

Raman spectroscopy was applied to investigate the temperature dependent pyrolysis of Australian bituminous coal from 298 to 1473 K in argon and nitrogen atmospheres. The results indicated that the pyrolysis of Australian bituminous coal can be divided into three stages: 298–873 K, precipitation and volatilization of small molecule compounds (original in coal or decomposed by heat treatment); 873–1273 K, cracking and volatilization of macromolecular compounds; 1273–1473 K, graphitization of coke. After annealing at 1473 K, the ordered carbon content of coke is significantly related to the atmosphere of nitrogen or argon; nitrogen is conducive to the pyrolysis of coal. Annealing or holding time exhibits little effect on coal pyrolysis and coke structure evolution; however, long holding time is helpful for the volatilization of small molecules at low temperature.