Drying Curve Equation and Drying Time of Wet Materials

Zonal methods for calculating drying time, based on graphical differentiation of the drying curve, are presented. An analysis of drying time calculation based on the drying rate curve is given using the methods of A. V. Lykov, V. V. Kras nikov, S. M. Smirnov, B. S. Sazhin, and P. S. Kuts. The methods for calculating the drying time based on the relative drying rate without using the drying rate curve are considered. A generalized dimensionless drying curve as a function of the genera lized drying time is given based on the method of generalized drying curves of G. K. Filonenko and V. V. Krasnikov. Possible methods for approximating the equation of a generalized drying curve by hyperbolic, power, and exponential dependencies are considered. The necessary conditions are given for determining the suitability of these dependencies for describing the equations of the drying curves and deriving the equations. Equations of the drying curve are obtained from these dependencies and formulas are given for calculating the drying time for the processes of drying ceramics, asbestos, and felt. Based on the dependence of the complex variable of the relative drying rate on the ratio of the current to the initial moisture content, for the processes of drying ceramics, asbestos, and felt, equations are given for calculating the drying time. The methods for expres sing the drying curve in the form of dependencies of relative moisture content on the generalized drying time are considered. Methods for calculating the drying time based on the relative drying rate are presented. Based on the dependence of the rela tive drying rate on the dimensionless moisture content, approximate methods for determining the critical moisture content of the material are given. The reliability of the obtained equations is checked and the calculated values are compared with the experiment. The calculation error is within the range of experimental accuracy.

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