Drying and Humidification Rates for Cotton Lint

Abstract

Equipment and techniques were developed to study cotton moisture absorption and desorption rates at temperatures ranging from 49 to 91 C (120 to 196 F). The data provided valuable insight into the moisture-time relationships for cotton lint. The moisture data was transformed and found to fit a theoretical, exponential decay function. Nonlinear regression analysis was used to fit the value of the coefficients in the theoretical equation to the experimental data. Results indicate that both temperature and air condition (dry or humid) significantly affect the diffusivity (rate) parameter in the nonlinear equations. As expected, higher moisture transfer rates occurred at higher temperatures and the drying rate was significantly higher than the humidification rate for cotton lint at the same temperature. When the diffusivity coefficients from this study and from the literature are plotted against temperature, the coefficients for the dry air produce an almost linear relationship with temperature. Generalized equations for moisture absorption and desorption were also developed, using historical data along with data from this study, for a temperature range of 5 to 90 C (41 to 194 F).