Meikuang Anquan (May 2024)
Effect of external moisture on pore structure and spontaneous combustion characteristics of long-flame coal
Abstract
To research the pore structure and oxidation spontaneous combustion characteristics of coal after water immersion, long-flame coal was prepared into water-soaked coal with water content of 4%-20%. Automatic specific surface area analyzer and simultaneous thermal analyzer were adopted to analyze the pore structure characteristics and thermal weight loss law of raw coal and water-soaked coal. The characteristic temperatures of raw coal and water-soaked coal were obtained, and apparent activation energy was calculated by kinetic analysis. Results indicated that with the increase of moisture in coal, the specific surface area and average pore diameter of coal gradually increased. Meanwhile, the high adsorption temperature and dry crack temperature gradually increased. In the range of 30-125 ℃, the inhibition of water on coal oxygen reaction was dominant. When the temperature exceeded 125 ℃, the maximum mass temperature and ignition point temperature of water-soaked coal were lower than that of raw coal, the water in coal evaporated, and the large pores of the water-soaked coal were conducive to oxygen adsorption, which was mainly manifested in the promotion effect. Meanwhile, the apparent activation energy of coal with water content of 12% was the smallest and the promotion effect was the best.
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