Study of Structural Changes in Dried Bituminous Coal Soaked in Water and Its Effect on Spontaneous Combustion in Coal Mines

Abstract

This study examines the effects of changes in microphysical structure of dried bituminous coal soaked in water on its propensity to spontaneously combust. A scanning electron microscope (SEM) and low temperature liquid nitrogen adsorption experiments were used to determine the changes in specific surface area, total pore volume, average pore size, and approximate fracture dimensions in the coal samples. Experimental results show that compared with raw coal samples, pores and fractures on the surface of dried bituminous coal soaked in water are enlarged and the pores and fractures also increased in numbers. The results also show that, for dried bituminous coal soaked in water, specific surface area and total pore volume decrease, average pore size increases, and the connectivity of pores and fractures is improved. This contributes to increased oxygen adsorption and increases the risk of coal oxidation and spontaneous combustion of bituminous coal.