The Effect of Rotor Geometry on Particle Size Characteristics for Knife-milled Wheat Straw

Abstract

The paper aimed to experimentally identify the effect of rotor blade geometry on particle size characteristics for the knife-milled wheat straw of 12.5 wt % moisture content. Biomass was systematically reduced in size using two-blade rotor geometries (linear and screw), varying the following conditions: rotor speeds of 10.2 - 20.4 m s-1 and screen sieve sizes of 0.75 - 10 mm. It was identified that rotor blade geometry affected particle size. The higher the rotational rotor speed and the screen sieve size, the higher the difference in particle size characteristics. The original empiric model was derived and calibrated by studying the mutual relationships among process variables. The model allows predicting characteristic particle size D50 for individual rotor blade geometries, knowing rotor speed and screen sieve size. The accuracies of R2 = 0.94 for linear- and R2 = 0.92 for screw-blade rotor geometry were reached for particle size estimation using the derived model.