Research on dust control of mobile straw granulator

Abstract

High particle concentrations, large sizes and coupled flows areproduced in mobile straw granulators during operation. To control the dust emissions and reduce the mass ratio of the dust into the press device of the granulator, an Eulerian multiphase flow model was first used to analyze the effects of the storage cage structure, flow velocity at the duct outlet, ambient wind speed and particle size on dust emissions. The flow characteristics of the particle distribution, particle trajectory and particle concentration were studied and verified by experiments. Second, a diversion duct was designed to reduce the phenomenon of dust emission and sedimentation by using the principle of gravity settlement. The results showed that the structure of the diversion duct and dense storage cage could improve the flow characteristics at the outlet, change the coupled effect between flow and particles, and play a key role in reducing dust concentration. The diffusion distance of dust emission could be restrained, and the mass ratio of dust entering the press device could be increased by reducing the outlet wind speed. When the air flow velocity at the duct outlet was reduced from 7.5 to 2.9 m∙s−1, the horizontal dispersion distance of dust was reduced to 4.33 m, and the mass of dust entering the press device accounted for approximately 60%. The difference in diffusion distance between particles with diameters of 30 and 5 μm was only 0.47 m, and the particle size had little effect on the dust emission distance. The spread of dust emissions could be inhibited in breezy and calm weather. The results provide a reference for the modification of farm equipment.