Competitive adsorption difference during coal spontaneous combustion process in noble gas atmosphere

doi:10.16265/j.cnki.issn1003-3033.2020.04.010

Abstract

Abstract: In order to explore spontaneous combustion characteristics in low temperature oxidation process of coal after absorption in CO₂ and N₂ atmospheres, with anthracite coal in No. 9 coal seam of Sihe No. 2 mine taken as research object, warming test and TG test of coal during low temperature oxidation were conducted to analyze gas product characteristics and weight loss characteristics of CO and CH₄ during spontaneous combustion of coal. Then, a physical adsorption model of different gas molecules, such as O₂, CO₂ and N_2, was established on the surface of coal macromolecules, and adsorption of O₂ gas molecules was analyzed from a micro perspective using grand canonical Monte Carlo simulation (GCMC) method. Finally, difference in competitive adsorption between mixed gas molecules on surface of coal macromolecules were discussed. The research shows that spontaneous combustion characteristics of coal in low temperature oxidation process change after adsorption in CO₂ and N₂ atmospheres, with concentration of CO and CH₄ gas products being reduced and rate of weight loss of coal spontaneous combustion decreasing, thus inhibiting low temperature oxidation capacity of coal. The mixed adsorption of coal macromolecules on gas molecules, like CO₂ and N₂, suppresses their adsorption of O₂ molecules. And gas competitive adsorption on coal surface ranks as H₂O>CO₂>N₂>O₂>CH₄>CO.

Key words: spontaneous combustion of coal, noble gas, thermogravimetric(TG), gas product characteristics, adsorption competition, oxidation ability

CLC Number:

X936

LOU Hezhuang, JIA Tinggui. Competitive adsorption difference during coal spontaneous combustion process in noble gas atmosphere[J]. China Safety Science Journal, 2020, 30(4): 60-67.

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