Application of small angle X-ray scattering in evaluation of pore structure of superfine pulverized coal/char

Abstract Superfine pulverized coal as a new energy utilization method plays a significant role in alleviating pollutant emissions. It is of great interest to study the physicochemical properties of superfine pulverized coal. Pore structures acting as the channel of heat and mass transfer change with temperatures, coal ranks and pyrolysis atmospheres, etc. The investigation of the pore structure evolution during coal pyrolysis is beneficial for understanding the pyrolysis mechanisms, and guiding the practical application of superfine pulverized coal. Synchrotron radiation small angle X-ray scattering (SAXS) is a nondestructive test method with high accuracy, which can detect the open and closed pores simultaneously. Furthermore, the fractal dimensions were adopted here to characterize the coal pore structures quantitatively. The final results indicated that the fractal dimensions of pore surfaces decreased with the increase of coal ranks. Moreover, as elevating the pyrolysis temperatures, the fractal dimensions increased initially up to about 550 °C, and decreased afterwards in the lower temperature region (