Dielectric and thermal properties of sweet sorghum biomass
Document Type
Article
Publication Date
1-1-2014
Abstract
Sweet sorghum has recently received a lot of attention as a potential biomass feedstock in the United States. This study investigated the dielectric properties (dielectric constant ε’ and dielectric loss factor ε’’) of sweet sorghum biomass as a function of frequency (around 915 and 2450 MHz, respectively) and water content – wH2O (important for microwave drying and processing operations). Fundamental thermal properties needed in process design calculations (specific heat, thermal conductivity, thermal diffusivity) were also determined using a thermal conductivity probe method. Dielectric constant decreases with frequency at both frequency ranges. At 915 MHz, ε’ ranged from 2.73 at wH2O = 49.5% to 1.1 at wH2O = 0%, whereas at 2450 MHz, ε’ ranged from 2.67 at wH2O = 55.4% to 1.03 at wH2O = 0%. The dielectric loss factor ranged from 0.44 at wH2O = 49.5% (at 915 MHz) and 0.7 at wH2O = 55.4% (at 2450 MHz) to near zero at wH2O = 0% for both frequencies. Thermal conductivity, specific heat, and thermal diffusivity were determined to be, respectively, 0.13±0.003 W•m-1•K-1, 2321.2±43.12 J•kg-1 •K-1, and 0.37±0.01 mm2•s-1. These results can be used for design of microwave processing systems for sweet sorghum biomass, as well as for process design calculations involving various heat-based unit operations.
Publication Source (Journal or Book title)
Journal of Microwave Power and Electromagnetic Energy
First Page
244
Last Page
260
Recommended Citation
Fennell, L., & Boldor, D. (2014). Dielectric and thermal properties of sweet sorghum biomass. Journal of Microwave Power and Electromagnetic Energy, 48 (4), 244-260. https://doi.org/10.1080/08327823.2014.11689888