Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 30, 1998
Publication Date: N/A
Interpretive Summary: Moisture affects every aspect of cotton harvesting and processing. Excessive moisture results in grade losses, fiber deterioration, and decreased machine performance while low moisture can cause fiber breakage and results in operating difficulties. Techniques and procedures were developed for determining the effects of temperature on moisture absorption nrates at 20, 35, 50, 75, 100, 120, and 130 deg C. Temperature had definite effect on the drying rates of the acid delinted cotton seed. The data for the drying portion of the study were found to fit equations shown in the literature. The moisture absorption data showed evidences of metabolic activity after a few hours. This information will be used in conjunction with equilibrium moisture data to estimate the moisture content of harvested seed cotton during cotton harvesting and ginning.
Technical Abstract: Moisture control during the harvesting, storage, and processing phases of cotton production is essential for producing a quality product. Basic information relating environmental parameters to equilibrium moisture content and the moisture transfer rates for cotton and its component parts will lead to a better understanding of the processes involved and design and control criteria for cotton conditioning equipment. This report describes the moisture desorption rates for acid delinted cotton seed. Absorption values are shown for temperatures of 20 deg C and 35 deg C and desorption values for temperatures ranging from 20 deg C to 130 deg C (68- 266 deg F). The desorption (drying) moisture data were plotted against time and found to be exponential in nature. Nonlinear regression analysis was used to fit the value of the coefficients in the theoretical falling rate equation to the experimental data. The desorption (drying) data fit the theoretical falling rate (exponential decay) function reasonably well, especially at temperatures above 100 deg C (212 deg F). Temperature significantly affected the coefficient containing the diffusivity parameter in the drying equations. A generalized solution of the falling rate equation was developed as a function of absolute temperature (for both acid delinted and gin run cotton seed), which should be suitable for engineering calculations. Results indicate that moisture absorption by cotton seed undergoes two absorption phases. The second phase, which shows an increased moisture absorption rate after a leveling off period, may indicate increased metabolic activity. We observed no obvious differences in the drying rates for the acid delinted cotton seed when compared to gin run cotton seed.