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

•A comprehensive study on the pore structures of superfine pulverized coal was conducted.•Synchrotron radiation-induced small angle X-ray scattering was adopted and results were analyzed quantitatively through fractal dimensions.•The effect of particle size on the pore network was concerned.•The influence of different pyrolysis conditions on the changing process of pore structure was investigated.