Study of fractal based oxygen adsorption experiment of porous coal

Abstract

Coal is China?s main energy source and fuel. Coal spontaneous combustion is one of the most prominent issues that threaten the production safety of coal mining, storage, and transportation. In order to explore the factors affecting coal spontaneous combustion, we investigated the pore structure characteristics of the coal based on the fractal theory, through the low temperature liquid nitrogen adsorption experiment of coal. The fractal dimension of the coal sample was calculated, and the oxygen adsorption quantity of the same coal sample was obtained by using the physical adsorption experiment of coal. Experimental and fitting results showed that coal sample has obvious surface fractal dimension features and pore structure fractal features. Fractal dimension expressed coal oxygen adsorption well. In the meantime, the coal samples with lower fractal dimension, higher temperature, smaller porosity usually have less oxygen adsorption quantity. This research cannot only enrich the study of oxygen adsorption in porous media such as coal, but also help to understand its spontaneous combustion mechanism in depth, thereby reducing the occurrence of spontaneous combustion disasters.