Study of parameters for the analysis of corn drying
1988
Arunee Pudpong | Somchart Soponronnarit | Warunee Tia (King Mongkut's Inst. of Technology Thonbyri, Bangkok (Thailand). School of Energy and Materials)
In this study, the sorption isotherms of cornvarieties Suwan 1 and Suwan 2 were determined at temperatures 35 to 70 deg C for relative humidity ranging 10-90 percent by using the static method. The effects of temperature, hysteresis and varieties on the sorption isotherms were investigated. The mathematical models based on the equations of Henderson, 1952, Chungand Pfost, 1967 and Brunaueret et al., 1938 (BET) were developed to fit the experimental data. Besides some physical properties of both varieties which were bulk density and void fraction for moisture content ranging 7-35 percent dry basis were determined. The result showed that for the same variety, sorption isotherm at low temperature was higher than at high temperature. The effect of hysteresis on sorption isotherm was more significant than the effect of variety. Henderson, 1952 ann Chung and Pfost, 1967 equations provided a suitable description than the other. Thin-layer drying rate for corn were determined as effected by drying air temperature, air flow rate and initial moisture content. Drying air temperature and initial moisture content had the greatest effect on drying rates. Air velocity had smaller effects. The data were fit to models of the form suggested by Page, 1949 and the one analogy to Newton's law of cooling. The current models describe thin-layer drying rate for corn in the temperature range from 45 to 67 deg C and initial moisture content range from 18 to 36 percent dry basis. These results showed that Page (1949)'s equation provided a suitable description of thin-layer drying rate. It was found that bulk density incresed linearly with moisture content but void fraction decresed linearly with moisture content.
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