Potential safety evaluation method based on temperature variation during gas adsorption and desorption on coal surface

Abstract

The mechanism of gas adsorption and desorption is very important for mine safety. Meanwhile, the gas adsorption or desorption process may lead to temperature or heat variation. In order to reveal this phenomenon, the relationship between gas adsorption (and desorption) and temperature of three different coal samples was experimentally investigated under different temperatures, coal ranks and equilibrium pressures. It’s found that gas adsorption quantity, gas adsorption rate and temperature variation decreased with temperature. Additionally, the variation of equilibrium pressures and the gas adsorption quantity were larger when the particle size was smaller. The more the equilibrium pressure is, the more the maximum temperature variation and the rate of temperature variation are. On the other hand, the higher the temperature is, the more the desorption quantity is, but the desorption rate and the maximum temperature variation of dropping increase with the temperature increasing. And the desorption quantity and the rate of desorption temperature increased when the particle sizes became larger. Besides, the gas adsorption quantity of coal samples with high metamorphic grade was larger under same equilibrium pressure, the temperature variation of dropping of ZX-2# is as much as the ML-8#. As a result, ZX-2# coal can accumulate a large amount of heat energy and it belongs to soft coal, which is easy to cause the outbursts. It also can be concluded that the bigger the equilibrium pressure is, the bigger the desorption quantity and desorption rate are. And desorption temperature decline greatly with the increase of equilibrium pressures.