Analysis of initial condensation and the effects of distillers' spent grain pellet orientation and superheated steam operating parameters on effective moisture diffusivity

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Bourassa, Justin
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Distillers’ spent grain (DSG) is a by-product of ethanol production and used for swine feed supplement due to its nutrient composition. Lowering the moisture content of DSG using superheated steam (SS) drying can be more energy efficient compared to hot air drying. One objective was to investigate parameters associated with SS drying on DSG including maximum condensation, condensation time, and restoration time. Increasing SS temperature from 120 to 180 °C and SS velocity from 1.0 to 1.4 m/s resulted in a 97% and 67% decrease in maximum condensation, respectively. Another objective was to determine the effect of SS temperature, velocity, and pellet orientation on effective moisture diffusivity of DSG pellets. The diffusion model was based on finite cylinder geometry accounting for volumetric shrinkage. The diffusivity coefficient was determined to be 1.56 × 10-8 m2/s. A significant effect of pellet orientation on moisture diffusivity was found during the constant drying-rate period.
Distillers' spent grain, Diffusivity, Initial condensation, Finite cylinder, Superheated steam