Study of flow characteristics of biomass and biomass–coal blends

• A model on the angle of internal friction has been proposed for biomass–coal blend.
• The blend’s best flow for aerated and discharge was obtained at 10 wt% of biomass.
• The effect of aeration on the flow behavior of materials was studied in detail.

The flow characteristics of biomass and biomass–coal blends were demonstrated experimentally by investigating the shear properties, flow energy and aeration with a FT4 Powder Rheometer. The results show that the addition of biomass into coal has no effect cohesion strength but significantly increases the angle of internal friction. We propose an improved empirical correlation to describe the quantitative relationship between angle of internal friction and particle shape factor, which agrees well with the experimental data. With the increase of biomass mass fraction, the flow energy was found to exponentially increase and the flow of blends became unstable, which produce a critical mass fraction to obtain an optimum flow performance of biomass–coal, i.e., 10 wt%. It is apparent that the flow behavior of biomass–coal blends is very sensitive to aeration, but torpid for biomass particles due to its high permeability. It indicates that biomass is not suitable for dense-phase pneumatic conveying.