Study on combustion characteristics and thermokinetic parameters of lignite from Lunxin Coal Mine in Inner Mongolia
MA Li
LI Dengyu
LIU Hu
FAN Jing
ZHAO Xiangkai
YAN Yueyuan
CHEN Rong
PEI Guangwei
Abstract：The 11#coal seam of Luxin Coal Mine in Inner Mongolia is lignite,which belongs to the easy spontaneous combustion coal seam,and the risk of coal spontaneous combustion is large.In this study,lignite from Luxin Coal Mine in Inner Mongolia was selected.The combustion process of lignite at different heating rates(10,20,30,40℃/min)and oxygen volume fractions(9,13,17,21%)was studied by synchronous thermal analyzer.The thermokinetic parameters such as characteristic temperature point,weight loss rate,flammability index,comprehensive combustion characteristic index and apparent activation energy were compared and ana-lyzed.The results show that the characteristic temperature increases with the increase of heating rate and the decrease of oxygen volume fraction.The heating rate and oxygen volume fraction had no significant effect on the mass loss and heat release during the weight loss stage.The increase of oxygen volume fraction and heating rate will strengthen the oxidation reaction of pulverized coal in the pyrolysis combustion stage and increase the heat release rate,and the maximum weight loss rate,comprehensive combustion characteristic index,flammability index,heat release and other characteristic parameters increase accordingly.When the heating rate is 40℃/min,the maximum weight loss rate is 14.77%/min,which is 25.8%higher than the heating rate of 10℃/min.The maximum weight loss rate at the oxygen volume fraction of 21%is 1.6 times higher than that of 9%,and the total heat release increases by 3.7 times.When the heating rate and oxygen volume fraction are the highest,the flammability index and the comprehensive combustion characteristic index reach the maximum values of 13.64×10-5 and 11.35×10-7,respectively.The apparent activation energy increases with the increase of oxygen volume fraction and increases first and then decreases with the increase of conversion rate.The conver-sion rate reaches its maximum value of 197.9 kJ/mol at 0.30.The increase of oxygen volume fraction and heating rate prompts the increase of active structure and activation energy of incomplete reaction in pulverized coal,and the coupling of the two accelerates the oxidation reaction rate.
Keywords：coal spontaneous combustionlignitecharacteristic temperatureheat releasethermokinetic parameters
Publication Date：2025-10-30
Online Publishing Date：2025-10-28(First online date of this platform, not the publication date of the document)
Pages：9( 14-22 )