Thermal characteristics and kinetic analysis of coal-oxygen reaction under the condition of inert gas

• Published in: International journal of coal preparation and utilization 2022-03, Vol.42 (3), p.846-862
• Main Authors: Liu, Hongwei, Wang, Fei
• Format: Article
• Language: English
• Subjects: Activation energy; Burnout; Carbon dioxide; Coal; Coal mine goaf fire; Coal mines; Decomposition; Extinguishing; Fire prevention; Heat transfer; Ignition temperature; inert gas; kinetic analysis; Oxygen; Rare gases; Spontaneous combustion; Temperature; TG-DTG-DSC experiments; thermal characteristics
• ISSN: 1939-2699; 1939-2702
• DOI: 10.1080/19392699.2019.1671377

To ascertain fire prevention and extinguishing mechanism of inert gas in coal mine goaf, TG-DTG-DSC experiments of coal-oxygen reaction at 30-850℃ under N 2 and CO 2 conditions were carried out, and the thermal characteristics and kinetic factors were analyzed. The process of coal-oxygen reaction was divided into five stages by the four characteristic temperatures of T 1 (temperature at which water evaporates completely), T 2 (temperature at which coal begins to decompose intensely), T 3 (ignition temperature) and T 4 (burnout temperature). With the decrease of O 2 concentration, T 2 , T 3 , and T 4 increased, the total mass loss and heat release decreased, and the decomposition degree increased. The injection of N 2 and CO 2 reduced the apparent activation energy and pre-exponential factor of T 1 -T 2 , T 2 -T 3 and T 3 -T 4 stages, and there was dynamic compensation effect between activation energy and pre-exponential factor. Under the same O 2 concentration conditions, the effect of CO 2 was more significant than that of N 2 . Reducing oxygen concentration by injecting N 2 and CO 2 could rapidly reduce the degree of coal-oxygen reaction rate. This study is of great significance for the prediction of coal spontaneous combustion and the using of N 2 and CO 2 coal fire prevention and extinguishing technology.