Physical Properties and Concentration of Grain Dust Generated from Post-Harvest Processing of Rough Rice

Abstract

<abstract><title><italic>Abstract.</italic></title> This research focuses on estimation of the particle size, concentration level, and terminal velocity of grain dust produced during post-harvest processing of rough rice in order to provide critical information for efficient dust collector design. Dust concentration levels were relatively low at indoor processing units, with pre-cleaners, brown rice processes, and milled rice processes indicating 1.3 to 7.7 mg m^-3. Outdoor processing units, such as receiving, drying, and storage, indicated higher dust concentration levels (5.1 to 9.1 mg m^-3). A model of the terminal velocity of grain dust was introduced by two linear regression equations: one for particles smaller than 200 μm, and the other for particles between 200 and 2,000 μm. Coefficients of determination were 0.9266 and 0.9770, respectively, indicating the significance of the model. The particles smaller than 200 μm showed relatively lower terminal velocity (0.15 to 0.26 m s^-1), while the larger particles (200 to 2,000 μm) showed relatively higher terminal velocity (0.9 to 2.2 m s^-1).