Thermokinetic Behavior and Microcharacterization during the Spontaneous Combustion of 1/3 Coking Coal

ABSTRACT

Thermal analysis was used to investigate the oxidation and heat-release characteristics of four coal samples from the Huainan mining area in China. Temperature and the evolution of heat and gaseous products were studied to identify each sample’s ignition temperature and inform fire-prevention advice to avoid the spontaneous combustion of the coals studied. Thermogravimetry–differential scanning calorimetry (TG–DSC) tests demonstrated lower heating rates resulted in lower characteristic temperatures, corresponding to a greater propensity for spontaneous combustion. Using the Flynn–Wall–Ozawa method, spontaneous combustion was predicted from approximately 300°C, which agreed well with the TG–DSC analysis. The apparent activation energies for combustion were also obtained and gas products that were released throughout the entire oxidation process were monitored. Simultaneous thermal analysis–Fourier transform infrared spectroscopy was used to explain the changes in the evolution of CO and CO₂, the results of which agreed well with those of TG.

KEYWORDS:

• Gas release
• functional group
• characteristic temperature
• Flynn–Wall–Ozawa method
• apparent activation energy

Acknowledgments

The authors gratefully acknowledge Dr. Frank Oreovicz (Retired) of Purdue University (West Lafayette, Indiana, USA) for technical support and Liwen Bianji, Edanz Group China (www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript.

Additional information

Funding

This research was sponsored by the National Natural Science Foundation of China (No. 5180-4247), the China Postdoctoral Science Foundation (No. 2016-M-590963), and the Industrial Science and Technology Project of Shaanxi Province, PR China (No. 2016-GY-192).