The article presents research on the optimal granulation of plant biomass for uniform drying in vibrating fluidized bed dryers. The biomass self-feeding vibrating bed dryer solution uses warm air or from the atmosphere and allows adjustments of the vibration frequency, amplitude and tilting angle of the vibrating tray necessary to adjust the transit time of the biomass through the dryer, consequently of the degree of biomass drying at the output of the dryer. Numerical simulation was performed with a proprietary 2D multibody dynamics software developed in the institute, which only analyzes the mechanical aspects of the dryer, the interaction between the biomass fragments and between them and the vibrating tray of the dryer. The numerical simulation results will be presented in two cases, in the first case (C#1) the industrial vibrator rotates in the direction of movement of biomass fragments and in the second case (C#2) in the reverse direction of the movement of biomass fragments, for eight types of fragments.