Porosity changes in bituminous and anthracite coal with ultrasonic treatment

Improving pore structures is key for enhancing coalbed methane (CBM) recovery. The variations in pores of Chinese bituminous and anthracite coal were analysed by using low-pressure N2 gas adsorption and CO2 gas adsorption during 20 kHz and 50 kHz ultrasonic treatment. Although the shape of the physisorption isotherm and hysteresis loop, that indicate the pore type of coal, were not changed after ultrasonic treatment, the pore size distribution...