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

This document is currently not available here.

Share

COinS