During the process of pneumatic conveying of fine particles, the flow mode may change from dense to dilute. In studying this mode change, we evaluate three parameters (Hurst exponent, Shannon entropy, and phase-space attractor size) used in signal analysis. Experimental data of pneumatic conveying of fly ash at three locations along a 173-m-long pipeline were used for this analysis. Variations in magnitude of the Hurst exponent, Shannon entropy, and size of the phase space attractor exhibit different trends in their variations for dense and dilute mode of flow. From these trends it is possible to predict the change from dense to dilute mode and the location along the length of the pipeline of this change in mode of flow. © 2016 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences