Thermophysical properties of laboratory-prepared corn/wheat dried distillers grains and dried distillers solubles dehydrated with superheated steam and hot air

Abstract

ABSTRACTThe objective of this study was to dry–wet distillers grains and centrifuged solubles and to examine the effect of two different drying media, superheated steam and hot air, at different drying temperatures (110, 130, and 160°C), moisture contents (5–30% wb), and percentages of solubles’ presence (0 or 100%) on some thermophysical properties of laboratory-prepared corn/wheat dried distillers co-products, including geometric mean diameter (dg), particle density (ρp), bulk density (ρb), bulk porosity (ϵb), specific heat (C), effective thermal diffusivity (αeff), and bulk thermal conductivity (λb). The values of dg of corn/wheat dried distillers co-products ranged from 0.358 ± 0.001 to 0.449 ± 0.001 mm. Experimental values of ρp, ρb, and ϵb varied from 1171 ± 6 to 1269 ± 3 kg m−3, from 359 ± 7 to 605 ± 5 kg m−3, and from 0.54 ± 0.01 to 0.71 ± 0.01 kg m−3, respectively. The values of αeff were between 0.58 × 10−7 and 0.93 × 10−7 m2 s−1. The calculated values of C ranged from 1887 ± 11 to 2599 ± 19 J kg−1 K−1, and the values of λb of corn/wheat dried distillers co-products ranged from 0.06 ± 0.01 to 0.09 ± 0.01 W m−1 K−1. Multiple linear regression prediction models were developed to predict the changes in dg, ρp, ρb, ϵb, C, αeff, and λb of laboratory-prepared corn/wheat dried distillers co-products with different operational factors.