Simulation And Experiment Of Adsorption Of Oxygen In Coal Porous Media

Coal resources occupy an important position in our country,and the mining technology of coal mines is constantly improving,but coal mine safety issues have not been well controlled.Among them,natural disasters such as fires and explosions caused by the spontaneous combustion of coal piles have caused serious harm to people’s lives and property.To this end,this subject conduct research on factors influencing coal spontaneous combustion.Based on the theory of coal-oxygen composite action,the factors influencing the oxygen adsorption capacity of coal during the physical adsorption stage are studied.The research of this subject may help to understand the mechanism of coal oxygen adsorption in the physical stage,and provide guidance for reducing the risk of coal spontaneous combustion.This article mainly carried out the following work:(1)Through the low temperature liquid nitrogen adsorption experiment of coal,the pore structure data of the experimental coal sample and the graph of the adsorption and desorption process of liquid nitrogen are obtained.According to the FHH equation,the fractal characteristics of the coal samples are calculated.The results show that the experimental coal samples show obvious fractal scaling laws in both the low-pressure section and the high-pressure section.(2)Perform industrial analysis on the same batch of coal samples to obtain the composition information of the coal samples.Through the physical adsorption experiment of coal,the oxygen adsorption capacity at different temperatures is obtained.Combined with the low temperature liquid nitrogen adsorption experiment,it is shown that the oxygen adsorption capacity of coal is positively correlated with the fractal dimension;Through component analysis,there is no obvious relationship between the degree of coal deterioration and the amount of oxygen adsorption;Under low temperature conditions,when the temperature is increased,the oxygen adsorption capacity of coal shows a downward trend.(3)Based on the self-similar fractal model,a pore-scale model for oxygen adsorption in porous coal media was established.Numerical simulation results show that the adsorption of oxygen depends on the pore structure and temperature of coal.Oxygen adsorption increases with increasing porosity,fractal dimension,and ratio of minimum pore size to maximum pore size.Edge effects can be seen near cavity/pore with low oxygen concentrations.Following the Langmuir adsorption theory,the relationship between oxygen adsorption and temperature was discovered,and a new formula for oxygen adsorption and porosity was proposed...