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

Abstract

In order to explore spontaneous combustion characteristics in low temperature oxidation process of coal after absorption in CO2 and N2 atmospheresꎬ with anthracite coal in No. 9 coal seam of Sihe No. 2 mine taken as research objectꎬ 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. Thenꎬ a physical adsorption model of different gas moleculesꎬ such as O2ꎬ CO2 and N2ꎬ was established on the surface of coal macromoleculesꎬ and adsorption of O2 gas molecules was analyzed from a micro perspective using grand canonical Monte Carlo simulation (GCMC) method. Finallyꎬ 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 atmospheresꎬ with concentration 第 4 期 娄和壮等: 惰性气氛对煤自燃过程的竞争吸附差异性研究 of CO and CH4 gas products being reduced and rate of weight loss of coal spontaneous combustion decreasingꎬ thus inhibiting low temperature oxidation capacity of coal. The mixed adsorption of coal macromolecules on gas moleculesꎬ like CO2 and N2ꎬ suppresses their adsorption of O2 molecules. And gas competitive adsorption on coal surface ranks as H2O>CO2>N2>O2>CH4>CO.